Electric circuits — Paper 3 · IGCSE Physics 0625

8 Fig. 8.1 shows an electrical circuit. For 12.0 V d.c. Examiner’s Use R A C B 4.0 Ω one metre resistance wire sliding contact Fig. 8.1 The resistance of the lamp is 4.0 Ω when it is at its normal brightness. (a) The lamp is rated at 6.0 V, 9.0 W. Calculate the current in the lamp when it is at its normal brightness. current = … [2] (b) The sliding contact C is moved to A. The lamp lights at its normal brightness. Calculate (i) the total circuit resistance, resistance = … [1] (ii) the potential difference across the 4.0 Ω resistor R. potential difference = … [1] (c) The sliding contact C is moved from A to B. (i) Describe any change that occurs in the brightness of the lamp. … [1] (ii) Explain your answer to (i). … … [2] (d) The 1 m wire between A and B, as shown in Fig. 8.1, has a resistance of 2.0 Ω. Calculate the resistance between A and B when (i) the 1 m length is replaced by a 2 m length of the same wire, resistance = … [1] (ii) the 1 m length is replaced by a 1 m length of a wire of the same material but of only half the cross-sectional area. resistance = … [1]

9 marks

Mark scheme: 8 (a) I = W/V or 9/6 C1 I = 1.5 A A1 2 (b) (i) 8 ohm A1 (ii) 6 V A1 2 (c) (i) brightness decreases/dimmer B1 (ii) resistance of circuit greater B1 current through lamp falls B1 3 (d) (i) 4 ohm A1 (ii) 4 ohm A1 2 [9] IGCSE – May/June 2006 0625 03

This question in 0625/31 May/June 2006

8 Fig. 8.1 shows a low-voltage lighting circuit. For Examiner’s 12 V d.c. Use supply X Y Z Fig. 8.1 (a) On Fig. 8.1, indicate with a dot and the letter S, a point in the circuit where a switch could be placed that would turn off lamps Y and Z at the same time but would leave lamp X still lit. [1] (b) (i) In the space below, draw the circuit symbol for a component that would vary the brightness of lamp X. (ii) On Fig. 8.1, mark with a dot and the letter R where this component should be placed. [2] (c) Calculate the current in lamp Y. current = … [2] (d) The current in lamp Z is 3.0 A. Calculate the resistance of this lamp. resistance = … [2] (e) The lamp Y is removed. (i) Why do lamps X and Z still work normally? … … (ii) The current in lamp X is 1.0 A. Calculate the current supplied by the battery with lamp Y removed. current = … [2]

9 marks

Mark scheme: 8 (a) switch in correct position B1 [1] (b) (i) rheostat/variable resistance symbol drawn B1 (ii) dot and R in line to 12 W lamp B1 [2] (c) Question deleted (d) R = V/I or 12/.3 C1 = 4Ω A1 [2] (e) (i) parallel circuit/all lamps connected separately across the 12V B1 (ii) 4 A A1 [2] [Total: 7] IGCSE - OCT/NOV 2006 0625 03

This question in 0625/31 Oct/Nov 2006

9 (a) Fig. 9.1 shows how a beam of electrons would be deflected by an electric field produced For between two metal plates. Examiner’s The connections of the source of high potential difference are not shown. Use + high – potential difference metal plate beam of electrons metal plate Fig. 9.1 (i) On Fig. 9.1, draw in the missing connections. (ii) Explain why the beam of electrons is deflected in the direction shown. In your answer, consider all the charges involved and their effect on each other. … … … … [5] (b) The deflection of a beam of electrons by an electric field is used in cathode-ray oscilloscopes. (i) What makes the electron beam move backwards and forwards across the screen? … … (ii) What makes the electron beam move up and down the screen? … … [2] (c) An a.c. waveform is displayed so that two full waves appear on the screen of a cathode- For ray oscilloscope. Examiner’s Use Fig. 9.2 shows the face of the oscilloscope. On Fig. 9.2, draw in the waveform. Fig. 9.2 [1]

8 marks

Mark scheme: 9 (a) (i) connections one to each plate M1 top one to +ve , bottom one to -ve A1 [2] (New PSU drawn C1) (ii) electrons negatively charged B1 one plate positively charged, one negatively charged B1 electrons attracted to +/repelled by – B1 [3] (b) (i) time base applied to X plates stated or described B1 (ii) a.c. or varying voltage applied to Y plates B1 [2] (c) 2 full waves, (equal about centre line) B1 [1] [Total: 8]

This question in 0625/31 Oct/Nov 2006

10 Fig. 10.1 shows a circuit that is used to switch on a lamp automatically when it starts to go For dark. Examiner’s Use D A + V – C B Fig. 10.1 (a) Write down the names of the components labelled A, B, C and D. A … B … C … D … [2] (b) Which of the four components A, B, C or D acts as a switch? … [1] (c) Explain why the lamp comes on as it goes dark. … … … … [3]

6 marks

Mark scheme: 10 (a) A – resistor B – LDR C – transistor D – lamp (–1 each incorrect) B2 [2] (b) C B1 [1] (c) resistance of LDR low in light, high in dark B1 increase of resistance/potential in circuit cause transistor to conduct (Vbe > 0.6 V) B1 switches lamp on B1 [3] [Total: 6]

This question in 0625/31 Oct/Nov 2006

8 Fig. 8.1 shows part of a low-voltage lighting circuit containing five identical lamps. 12 V d.c. supply A B C D E Fig. 8.1 (a) Complete the circuit, by the addition of components as necessary, so that (i) the total current from the supply can be measured, (ii) the brightness of lamp E only can be varied, (iii) lamps C and D may be switched on and off together whilst lamps A, B and E remain on. [4] (b) All five lamps are marked 12 V, 36 W. Assume that the resistance of each lamp is the same fixed value regardless of how it is connected in the circuit. Calculate (i) the current in one lamp when operating at normal brightness, current = … [1] (ii) the resistance of one lamp when operating at normal brightness, resistance = … [1] (iii) the combined resistance of two lamps connected in parallel with the 12 V supply, resistance = … [1] (iv) the energy used by one lamp in 30 s when operating at normal brightness. energy = … [1] Examiner’s Use (c) The whole circuit is switched on. Explain why the brightness of lamps A and B is much less than that of one lamp operating at normal brightness. … … … [2] [Total: 10]

10 marks

Mark scheme: 8 (a) connections such that all lamps will light B1 ammeter in correct position B1 variable resistor in correct position (condone poor symbol) B1 switch in appropriate position (could be 2 switches) B1 [4] (b) (i) 3 A B1 [1] (ii) 4Ω OR 12/his(i) correctly evaluated B1 [1] (iii) 2Ω OR ½ × his(ii) correctly evaluated B1 [1] (iv) 1080 J e.c.f. from (i) & (ii) if working shown B1 [1] (c) lamps in series M1 less current/less p.d. (across 1 lamp)/voltage shared/higher resistance A1 [2] NOT current shared [Total: 10] IGCSE – May/June 2007 0625 03

This question in 0625/31 May/June 2007

9 Fig. 9.1 is a sketch of some apparatus, found in a Science museum, which was once used to show how electrical energy can be converted into kinetic energy. When the switch is closed the wheel starts to turn. switch + metal d.c. supply supports – metal magnet spoked N wheel S N S small dish of mercury magnet wood base Fig. 9.1 (a) Explain why the wheel turns when the switch is closed. … … … … [2] (b) On Fig. 9.1, draw an arrow to show the direction of rotation of the wheel. [1] Examiner’s Use (c) The d.c. motor is another way to convert electrical energy into kinetic energy. In the space below, draw a labelled diagram of a d.c. motor. [3] (d) Describe how the split-ring commutator on an electric motor works. … … … … [2] [Total: 8]

8 marks

Mark scheme: 9 (a) current in spoke in magnetic field B1 causes force on spoke/wheel B1 [2] (b) arrow to indicate anticlockwise motion B1 [1] (c) outline of coil, pole pieces B1 d.c. supply connected to brushes B1 split rings connected to coil B1 [3] (d) brushes connect to other split ring every half turn/coil vertical B1 reverses direction of current every half turn/coil vertical B1 [2] [Total: 8]

This question in 0625/31 May/June 2007

10 Fig. 10.1 shows a circuit based on a transistor and a thermistor. power supply R2 R1 Fig. 10.1 (a) Describe the action of the thermistor in this circuit. … … … … [3] (b) State and explain how the circuit may be modified so that the lamp switches on at a different temperature. … … … [2] (c) State one practical use of this circuit. … [1]

6 marks

Mark scheme: 10 (a) when temperature rises resistance falls (or v.v.) M1 p.d. across it falls or equivalent (or v.v.) A1 idea of causes transistor to switch on lamp (or lamp off) A1 [3] (b) change value of R1/use variable res/swap R1 with something B1 brief explanation in terms of potential divider B1 [2] (c) fire alarm/refrigerator fail light/other automatic lighting system B1 [1] [Total: 6]

This question in 0625/31 May/June 2007

8 Fig. 8.1 shows two electrical circuits. V ammeter A 1 4.0 Ω ammeter P 4.0 Ω 6.0 Ω A 2 A 6.0 Ω P Q Q circuit 1 circuit 2 The batteries in circuit 1 and circuit 2 are identical. Fig. 8.1 (a) Put ticks in the table below to describe the connections of the two resistors P and Q. series parallel circuit 1 circuit 2 [1] (b) The resistors P and Q are used as small electrical heaters. State two advantages of connecting them as shown in circuit 2. advantage 1 … advantage 2 … [2] (c) In circuit 1, the ammeter reads 1.2 A when the switch is closed. Calculate the reading of the voltmeter in this circuit. voltmeter reading = … [2] (d) The two switches in circuit 2 are closed. Calculate the combined resistance of the two resistors in this circuit. combined resistance = … [2] Examiner’s Use (e) When the switches are closed in circuit 2, ammeter 1 reads 5 A and ammeter 2 reads 2 A. Calculate (i) the current in resistor P, current = … [1] (ii) the power supplied to resistor Q, power = … [1] (iii) the energy transformed in resistor Q in 300 s. energy = … [1] [Total: 10]

10 marks

Mark scheme: 8 (a) circuit 1 series AND circuit 2 parallel B1 (b) switch off each one separately ) one fails, other works ) both get full current/voltage/same voltage ) any 2 B1+B1 other good point e.g. more heat in parallel ) lower resistance ) (c) (total R =) 10 (Ω) C1 (V =) 12V A1 (d) 1/R = 1/4 + 1/6 (= 5/12) OR 1/R = 1/R1 + 1/R2 C1 2.4 (Ω) A1 (e) (i) 3(A) B1 (ii) 24W B1 (iii) 7200J e.c.f. (ii) B1 [Total: 10]

This question in 0625/31 Oct/Nov 2007

10 (a) Fig. 10.1 shows an AND gate with two inputs A and B and one output. A output B Fig. 10.1 State the output when (i) A is high and B is low, … [1] (ii) both A and B are low. … [1] (b) An electrical thermometer in a greenhouse gives a low output if the temperature is too low. A humidity sensor in the same greenhouse gives a high output if the humidity in the greenhouse is too high. An alarm sounds when both the temperature is too low and the humidity is too high. (i) Complete the diagram below to show how a NOT gate and an AND gate may be used to provide the required output to the alarm. [2] electrical thermometer alarm humidity sensor (ii) On your diagram, use either ‘high’ or ‘low’ to indicate the level of the inputs and outputs of both gates when the alarm sounds. [2] [Total: 6]

6 marks

Mark scheme: 10 (a) (i) low/0/off/no output B1 (ii) low/0/off/no output B1 (b) (i) temp sensor to NOT gate input, correct symbol B1 output of NOT gate (condone incorrect symbol) and humidity sensor to AND inputs (condone labelled box for AND gate) B1 (ii) NOT low in, high out B1 AND both inputs high, high output B1 Note: B0, B0 for states on wrong diagram. [Total: 6]

This question in 0625/31 Oct/Nov 2007

9 (a) Fig. 9.1 shows an a.c. supply connected in series to a diode and a resistor. For Examiner’s Use Fig. 9.1 On the axes of Fig. 9.2, draw a graph showing the variation of the current in the resistor. [1] current 0 time Fig. 9.2 (b) Fig. 9.3 shows four attempts, A, B, C and D, to connect a circuit known as a bridge For rectifier. Examiner’s Use The circuit is connected to a 12 V a.c. supply. A B 12 V 12 V red black red black C D 12 V 12 V red black red black Fig. 9.3 (i) In which circuit will the direction of the conventional current in the resistor always be from red to black? … [1] (ii) On the circuit you chose in (b)(i), clearly indicate with arrows the path of the conventional current in the circuit when the upper terminal of the a.c. supply is positive with respect to the lower terminal. [2] [Total: 4]

4 marks

Mark scheme: 9 (a) half-wave rectification clearly indicated (any wave shape, repeated): at least 2 humps with all spaces more than half width of hump, by eye. B1 (b) (i) A (c.a.o.) M1 (ii) For answers A and B only in (i), not C or D: Route to resistor: correct arrow on one downwards diode and nothing wrong on this route B1 Route from resistor: correct arrow on one downwards diode and nothing wrong on this route B1 [4] IGCSE – May/June 2009 0625 31

This question in 0625/31 May/June 2009

10 The circuit shown in Fig. 10.1 uses a 12 V battery. For Examiner’s Use 12 V A 16 8 S Fig. 10.1 (a) Switch S is open, as shown in Fig. 10.1. State the value of (i) the reading on the ammeter, reading = … [1] (ii) the potential difference (p.d.) across S. p.d. = … [1] (b) Switch S is now closed. (i) Calculate the current in the ammeter. current = … [2] (ii) Calculate the p.d. across the 8 resistor. p.d. = … [2] (c) The two resistors are now connected in parallel. For Examiner’s Calculate the new reading on the ammeter when S is closed, stating clearly any Use equations that you use. reading = … [4] [Total: 10] Question 11 is on the next page.

10 marks

Mark scheme: 10 (a) (i) 0 (A) / zero Unit penalty if wrong unit B1 (ii) 12 V B1 (b) (i) V / R OR V = IR in any form, letters, words or numbers C1 0.5 A A1 (ii) 8 × candidate’s (i) OR 8/24 × 12 C1 4 V OR 4.0 V e.c.f. A1 (c) 1/R1 + 1/R2 = 1/R OR R = R1R2 / (R1 + R2) in any form B1 5.3 (Ω) OR 5⅓ (Ω) OR 16/3 (Ω) C1 12 / candidate’s R C1 2.25 A c.a.o. A1 Alternatively: 12/16 (= 0.75) OR 12/8 (= 1.5) C1 12/16 (= 0.75) AND 12/8 (= 1.5) C1 Currents added C1 2.25 A c.a.o. A1 [10]

This question in 0625/31 May/June 2009

10 Alternating current electricity is delivered at 22 000 V to a pair of transmission lines. For The transmission lines carry the electricity to the customer at the receiving end, where Examiner’s the potential difference is V. This is shown in Fig. 10.1. Each transmission line has a Use resistance of 3 Ω. 22 000 V 3 Ω V 3 Ω Fig. 10.1 (a) The a.c. generator actually generates at a much lower voltage than 22 000 V. (i) Suggest how the voltage is increased to 22 000 V. … [1] (ii) State one advantage of delivering electrical energy at high voltage. … [1] (b) The power delivered by the generator is 55 kW. Calculate the current in the transmission lines. current = … [2] (c) Calculate the rate of loss of energy from one of the 3 Ω transmission lines. rate of energy loss = … [2] (d) Calculate the voltage drop across one of the transmission lines. For Examiner’s Use voltage drop = … [2] (e) Calculate the potential difference V at the receiving end of the transmission lines. V = … [2] [Total: 10] Question 11 is on the next page.

10 marks

Mark scheme: 10 (a) (i) step-up transformer B1 (ii) less heat/energy/power loss (from lines) / thinner wires (possible) B1 OR lower current NOT more efficient (b) P = V × I in any form, figures or symbols / (P =) VI C1 2.5 A A1 (c) P = I2R in any form, figures or symbols / (P =) I2R C1 18.75 W e.c.f. from (b) A1 (d) V = IR in any form, figures or symbols OR (V =) IR OR P = V2 / R in any form, figures or symbols OR (P =) V2 / R OR V = (PR)1/2 C1 7.5 V e.c.f. from (b) or (c) A1 IGCSE – October/November 2009 0625 31 (e) 22,000 – 7.5 – 7.5 OR 22,000 – 7.5 ecf C1 21,985 V e.c.f. (minimum 4 s.f.in this case) A1 OR 55,000 – 37.5 = 54962.5 (C1) 54962.5 / 2.5 = 21985 V (minimum 4 s.f. in this case) (A1) [10]

This question in 0625/31 Oct/Nov 2009

11 Fig. 11.1 is a schematic diagram of an electronic circuit controlling a lamp. For Examiner’s Use temperature sensor relay lamp B A light sensor Fig. 11.1 (a) State the names of the logic gates A and B. A … B … [2] (b) The output of the temperature sensor is high (logic 1) when it detects raised temperature. The output of the light sensor is high (logic 1) when it detects raised light levels. State the outputs of A and B when the surroundings are (i) dark and cold, output of A = … output of B = … [1] (ii) dark and warm, output of A = … output of B = … [1] (iii) bright and warm. output of A = … output of B = … [1] (c) (i) Suggest why B is connected to a relay, rather than directly to the lamp. … [1] (ii) The relay switches on when its input is high. In which of the three combinations in (b) will the lamp light up? … [1] (iii) Suggest a practical use for this circuit. … [1] [Total: 8]

8 marks

Mark scheme: 11 (a) A NOT or inverter B1 B AND B1 (b) (accept 1 or ON for HIGH, and 0 or OFF or NOT HIGH for LOW throughout) (i) A – HIGH and B – LOW (both) no e.c.f. B1 (ii) A – HIGH and B – HIGH (both) no e.c.f. B1 (iii) A – LOW and B – LOW (both) no e.c.f. B1 (c) (i) B cannot provide enough power / current for lamp, or equiv. OR allows remote lamp B1 (ii) the second one / dark and warm / HIGH, HIGH e.c.f. from (b) B1 (iii) warning if temperature in a closed / dark space (e.g. refrigerator, kiln) reaches too high a value N.B. “to switch on a lamp when it is dark and warm” not accepted B1 [8]

This question in 0625/31 Oct/Nov 2009

10 Alternating current electricity is delivered at 22 000 V to a pair of transmission lines. The For transmission lines carry the electricity to the customer at the receiving end, where the Examiner’s potential difference is V. This is shown in Fig. 10.1. Each transmission line has a resistance Use of 3 . 22 000 V 3 X V 3 X Fig. 10.1 (a) The a.c. generator actually generates at a much lower voltage than 22 000 V. (i) Suggest how the voltage is increased to 22 000 V. … [1] (ii) State one advantage of delivering electrical energy at high voltage. … [1] (b) The power delivered by the generator is 55 kW. Calculate the current in the transmission lines. current = … [2] (c) Calculate the rate of loss of energy from one of the 3 transmission lines. rate of energy loss = … [2] (d) Calculate the voltage drop across one of the transmission lines. For Examiner’s Use voltage drop = … [2] (e) Calculate the potential difference V at the receiving end of the transmission lines. V = … [2] [Total: 10] Question 11 is on the next page.

10 marks

Mark scheme: 10 (a) (i) step-up transformer B1 (ii) less heat/energy/power loss (from lines) / thinner wires (possible) B1 OR lower current NOT more efficient (b) P = V × I in any form, figures or symbols / (P =) VI C1 2.5 A A1 (c) P = I2R in any form, figures or symbols / (P =) I2R C1 18.75 W e.c.f. from (b) A1 (d) V = IR in any form, figures or symbols OR (V =) IR OR P = V2 / R in any form, figures or symbols OR (P =) V2 / R OR V = (PR)1/2 C1 7.5 V e.c.f. from (b) or (c) A1 (e) 22,000 – 7.5 – 7.5 OR 22,000 – 7.5 ecf C1 21,985 V e.c.f. (minimum 4 s.f.in this case) A1 OR 55,000 – 37.5 = 54962.5 (C1) 54962.5 / 2.5 = 21985 V (minimum 4 s.f. in this case) (A1) [10] IGCSE – October/November 2009 0625 32

This question in 0625/32 Oct/Nov 2009

11 Fig. 11.1 is an electronic circuit controlling an electric heater. For Examiner’s +5 V Use P electric Q relay coil heater 0 V a.c. Fig. 11.1 The relay contacts close when there is a current in the relay coil. (a) State the name of the logic gate in the circuit. … [1] (b) (i) State the name of component P. … [1] (ii) State what happens to P when its temperature falls. … [1] (c) For the relay to operate, the output of the gate must be high (logic 1). (i) What must be the input of the gate for the relay to operate? … [1] (ii) State what the resistance of P must be, compared with the resistance of Q, in order to give this input to the gate. … [1] (iii) Under what conditions will P have this resistance? … [1] (d) Suggest why component Q is a variable resistor, rather than one with a fixed value. … [1] (e) Suggest a practical use for this circuit. … [1] [Total: 8]

8 marks

Mark scheme: 11 (a) NOT or inverter B1 (b) (i) thermistor NOT thermal resistor B1 (ii) resistance increases OR voltage across it increases B1 (c) (i) LOW or 0 or off or NOT HIGH B1 (ii) (much) larger/ large / higher / high B1 (iii) low temperature e.c.f. from (c) (ii) B1 (d) to allow adjustment of the temp. at which relay will close / heater comes on B1 (e) automatic control or wtte of heating system / air-conditioning / automatic room heater OR thermostat OR any other sensible suggestion involving control of heating B1 [8]

This question in 0625/32 Oct/Nov 2009

8 (a) State the law of attraction and repulsion between electrostatic charges. For Examiner’s … Use … … [2] (b) Sometimes, when people have been riding in a car, they get an electric shock from the door handle as they get out of the car. Suggest why this happens. … … … [2] (c) A plastic rod is rubbed with a cloth and becomes positively charged. After charging, the rod is held close to the suspended table-tennis ball shown in Fig. 8.1. The table-tennis ball is covered with metal paint and is initially uncharged. nylon thread light table-tennis ball covered with metal paint positively charged rod Fig. 8.1 (i) Describe what happens to the charges on the metal-painted table-tennis ball as the positively-charged rod is brought close to the ball. … … … [1] (ii) The ball is attracted towards the charged rod. For Examiner’s Explain why this happens. Use … … … [2] (iii) When it is a few centimetres away from the rod, the ball is briefly touched by a wire connected to earth. In terms of the movement of charges, describe what happens to the charge on the ball. … … [2] [Total: 9]

9 marks

Mark scheme: 8 (a) same/like/similar charges repel (ignore poles repel) B1 unlike/opposite/different charges attract (ignore poles attract) B1 (b) idea of car/person (being) charged (by friction) B1 idea of charge/electrons going to/from/through person B1 (c) (i) electrons / -ve charges move towards the rod / to R (ignore just “attracted”) ignore any mention of +ve charges moving any mention of +ve electrons gets B0 B1 (ii) opposite charges attract OR electrons / -ve charges attracted to +ve / rod B1 attraction between opposite charges > repulsion between like charges OR – ve charges (are) close(r) (to the rod) B1 (iii) electrons / -ve charges flow (up) from earth/wire no e.c.f. from (i) ignore +ve charges moving, NOT +ve electrons B1 ball becomes –vely charged B1 [9]

This question in 0625/32 May/June 2010

9 The circuit in Fig. 9.1 contains a 4.0 V battery, whose resistance can be ignored. For Examiner’s There are also three resistors, a 3-position switch, S, and another component, P. Use 22 2 A S B 8 C P 4.0 V Fig. 9.1 (a) State the name of component P. … [1] (b) Deduce the resistance of the circuit when switch S is connected to (i) point A, resistance = … [1] (ii) point B. resistance = … [3] (c) State the current in component P when S is in position C, and explain your answer. For Examiner’s current = … Use explanation … … … … [2] (d) The 22 resistor is removed as shown in Fig. 9.2. 2 A S B 8 C P 4.0 V Fig. 9.2 Showing your working, decide which switch position will result in energy release from the circuit at the rate of 2.0 W. switch position = … [3] [Total: 10]

10 marks

Mark scheme: 9 (a) diode B1 (b) (i) 2 Ω B1 (ii) 24 OR 22 + 2 (Ω) seen C1 R 1R 2 1 / R = 1 / R1 + 1 / R2 (+ 1 / R3) OR (R =) R 1 + R 2 seen or used with any 2 resistors ignore extra resistance added to expression for R in equation C1 6 Ω A1 (c) N.B. marks may be scored anywhere in (c) (current =) zero / very small M1 diode reverse biased OR polarity wrong OR facing wrong way OR diode only conducts R / + to L / - A1 IGCSE – May/June 2010 0625 32 (d) use I = V / R OR P = VI OR P=V2 / R symbols, numbers or words M1 use of R = 8 (Ω) & correct calculation to give 2W OR R = 4 / 0.5 = 8 (Ω) OR R = 42 / 2 = 8 (Ω) OR any other calculation(s) using (I = V / R & P = VI) OR P = V2 / R to deduce 8 (Ω) M1 switch position B (NOTE: this is dependent on both M1s being scored) ignore any calculations using 2 Ω A1 [10]

This question in 0625/32 May/June 2010

8 (a) State the law of attraction and repulsion between electrostatic charges. For Examiner’s … Use … … [2] (b) Sometimes, when people have been riding in a car, they get an electric shock from the door handle as they get out of the car. Suggest why this happens. … … … [2] (c) A plastic rod is rubbed with a cloth and becomes positively charged. After charging, the rod is held close to the suspended table-tennis ball shown in Fig. 8.1. The table-tennis ball is covered with metal paint and is initially uncharged. nylon thread light table-tennis ball covered with metal paint positively charged rod Fig. 8.1 (i) Describe what happens to the charges on the metal-painted table-tennis ball as the positively-charged rod is brought close to the ball. … … … [1] (ii) The ball is attracted towards the charged rod. For Examiner’s Explain why this happens. Use … … … [2] (iii) When it is a few centimetres away from the rod, the ball is briefly touched by a wire connected to earth. In terms of the movement of charges, describe what happens to the charge on the ball. … … [2] [Total: 9]

9 marks

Mark scheme: 8 (a) same/like/similar charges repel (ignore poles repel) B1 unlike/opposite/different charges attract (ignore poles attract) B1 (b) idea of car/person (being) charged (by friction) B1 idea of charge/electrons going to/from/through person B1 (c) (i) electrons / -ve charges move towards the rod / to R (ignore just “attracted”) ignore any mention of +ve charges moving any mention of +ve electrons gets B0 B1 (ii) opposite charges attract OR electrons / -ve charges attracted to +ve / rod B1 attraction between opposite charges > repulsion between like charges OR – ve charges (are) close(r) (to the rod) B1 (iii) electrons / -ve charges flow (up) from earth/wire no e.c.f. from (i) ignore +ve charges moving, NOT +ve electrons B1 ball becomes –vely charged B1 [9]

This question in 0625/33 May/June 2010

9 The circuit in Fig. 9.1 contains a 4.0 V battery, whose resistance can be ignored. For Examiner’s There are also three resistors, a 3-position switch, S, and another component, P. Use 22 2 A S B 8 C P 4.0 V Fig. 9.1 (a) State the name of component P. … [1] (b) Deduce the resistance of the circuit when switch S is connected to (i) point A, resistance = … [1] (ii) point B. resistance = … [3] (c) State the current in component P when S is in position C, and explain your answer. For Examiner’s current = … Use explanation … … … … [2] (d) The 22 resistor is removed as shown in Fig. 9.2. 2 A S B 8 C P 4.0 V Fig. 9.2 Showing your working, decide which switch position will result in energy release from the circuit at the rate of 2.0 W. switch position = … [3] [Total: 10]

10 marks

Mark scheme: 9 (a) diode B1 (b) (i) 2 Ω B1 (ii) 24 OR 22 + 2 (Ω) seen C1 R 1R 2 1 / R = 1 / R1 + 1 / R2 (+ 1 / R3) OR (R =) R 1 + R 2 seen or used with any 2 resistors ignore extra resistance added to expression for R in equation C1 6 Ω A1 (c) N.B. marks may be scored anywhere in (c) (current =) zero / very small M1 diode reverse biased OR polarity wrong OR facing wrong way OR diode only conducts R / + to L / - A1 IGCSE – May/June 2010 0625 33 (d) use I = V / R OR P = VI OR P=V2 / R symbols, numbers or words M1 use of R = 8 (Ω) & correct calculation to give 2W OR R = 4 / 0.5 = 8 (Ω) OR R = 42 / 2 = 8 (Ω) OR any other calculation(s) using (I = V / R & P = VI) OR P = V2 / R to deduce 8 (Ω) M1 switch position B (NOTE: this is dependent on both M1s being scored) ignore any calculations using 2 Ω A1 [10]

This question in 0625/33 May/June 2010

8 The circuit in Fig. 8.1 contains a 2.0 V cell, whose resistance you should ignore. There are also three resistors, a 3-position switch, an ammeter and another component, P. 5.0 A S B 20.0 C A P 2.0 V Fig. 8.1 (a) State the name of component P. … [1] (b) Deduce the resistance of the circuit when switch S is (i) in position A, resistance = … [1] (ii) in position B. resistance = … [3] (c) Describe and explain what is seen on the ammeter when S is moved to position C. … … … … [2] (d) With S in position A, calculate how long it takes for the circuit to transfer 320 J of electrical energy to other forms. time taken = … [3] [Total: 10]

10 marks

Mark scheme: 8 (a) capacitor/capacitance/condenser B1 (b) (i) 5 Ω B1 (ii) 5 and 20 both used OR 25 C1 R 1 R 2 1/R = 1/R1 + 1/R2 OR (R =) seen or used C1 R 1 + R 2 4 Ω A1 (c) EITHER OR ammeter reading falls (to zero) no current/reading M1 as capacitor charges P already charged/does not conduct d.c. A1 (d) Formula for calculation of I (I = V/R) OR P (P = V2/R) C1 Use of energy = power × time in any form C1 400 s A1 [Total: 10]

This question in 0625/31 Oct/Nov 2010

11 When no circuit is connected to the input of a cathode-ray oscilloscope (CRO), there is a horizontal trace across the middle of the screen. Fig. 11.1 shows three circuits, each connected to a CRO. On the grid alongside each circuit, draw the trace that might be seen on the screen of the CRO. + battery CRO – a.c. supply CRO a.c. supply CRO [6] Fig. 11.1 [Total: 6]

6 marks

Mark scheme: 11 battery horizontal line across at least 4 squares M1 above or below horizontal centre line A1 a.c. supply alternating trace, any shape one or more cycles, at least 4 squares wide M1 above and below centre line, need not be symmetrical A1 a.c. supply only humps or only troughs seen, minimum 2 humps or troughs + diode M1 horizontal lines, approximately same width as humps or troughs, separating humps or troughs A1 [Total: 6]

This question in 0625/31 Oct/Nov 2010

6 (a) Explain what is meant by the terms analogue and digital, as applied to electronic circuits. analogue … … digital … … [2] (b) Describe, if necessary using a diagram, the function of an AND gate in digital electronics. … … … … [2] [Total: 4]

4 marks

Mark scheme: 6 (a) analogue any reading possible/idea of continuous variation of value of quantity B1 digital idea of two states only B1 (b) if both inputs are 1/high, the output is 1/high B1 only added to previous line OR if either or both inputs are 0/low, then output is 0/low B1 (accept both answers in form of a truth table) [Total: 4]

This question in 0625/32 Oct/Nov 2010

8 Fig. 8.1 shows a simple transformer. iron core primary secondary coil coil Fig. 8.1 (a) Describe how a voltage across the primary coil causes a voltage across the secondary coil. … … … … … … [3] (b) State what design feature would cause the voltage across the secondary coil to be larger than the voltage across the primary coil. … … [1] (c) The output of a power station is connected to a transformer, which you are to assume is 100% efficient. The input to the primary coil is 24 000 V, 12 000 A. The output from the secondary coil is 400 000 V. This is the voltage at which the electrical energy is transmitted through the transmission lines. Calculate the current in the secondary coil. current = … [2] (d) State two reasons why it is cheaper to transmit electrical energy at high voltage. 1. … … 2. … … [2] [Total: 8]

8 marks

Mark scheme: 8 (a) a.c./changing current (in primary) ) magnetic flux/field/force in core ) alternating/changing magnetic field ) any 3 B1 × 3 accept without magnetic if used in previous line field cuts secondary ) changing flux linkage in (secondary) ) induces emf/current in (secondary) ) (b) more/increasing turns on secondary OR less/decreasing turns on primary OR step up B1 (c) V1I1 = V2I2 in any form OR 24 000 × 12 000 = 400 000 × I2 C1 720 A A1 (d) less heat/energy/power loss OR more efficient energy transfer ) thinner/smaller cables ) less metal used ) any 2 B1+B1 less massive pylons ) ignore less electricity loss [Total: 8]

This question in 0625/32 Oct/Nov 2010

7 Fig. 7.1 shows how the resistance of the filament of a lamp changes as the current through the lamp changes. 30 25 resistance / 20 15 10 5 0 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 current / A Fig. 7.1 (a) Describe how the resistance of the lamp changes. … … … [2] (b) For a current of 0.070 A, find (i) the resistance of the lamp, resistance = … [1] (ii) the potential difference across the lamp, potential difference = … [2] (iii) the power being dissipated by the lamp. power = … [2] (c) Two of these lamps are connected in parallel to a cell. The current in each lamp is 0.070 A. (i) State the value of the e.m.f. of the cell. e.m.f. = … [1] (ii) Calculate the resistance of the circuit, assuming the cell has no resistance. resistance = … [2] [Total: 10]

10 marks

Mark scheme: 7 (a) increases (as current increases) M1 at an increasing rate A1 (b) (i) 25 Ω B1 (ii) IR in any form OR 0.070 x 25 C1 1.7/1.8 V A1 (iii) (P =) IV OR I2R OR V2/R in any form, numbers, symbols or words C1 0.12 W e.c.f. from (i)/(ii) A1 (c) (i) answer to (b)(ii) B1 (ii) use of 1/R = 1/R1 + 1/R2 OR R = R1R2/(R1 + R2) C1 12.5 Ω A1 [Total: 10]

This question in 0625/33 Oct/Nov 2010

4 The circuit of Fig. 4.1 is set up to run a small immersion heater from a 6.0 V battery. 6.0 V X A heater Fig. 4.1 (a) State the name and purpose of component X. name … purpose … [1] (b) The heater is designed to work from a 3.6 V supply. It has a power rating of 4.5 W at this voltage. (i) Calculate the current in the heater when it has the correct potential difference across it. current = … [2] (ii) Calculate the resistance of component X if there is to be the correct potential difference across the heater. The battery and the ammeter both have zero resistance. resistance = … [3] (c) Some time after the heater is switched on, the ammeter reading is seen to have decreased. Suggest why this happens. … … [1] (d) As an alternative to running the heater from a battery, it is decided to construct a circuit to enable it to be operated from the a.c. mains supply. Name the electrical component needed to (i) reduce the potential difference from that of the mains supply down to a potential difference suitable for the heater, … [1] (ii) change the current from a.c. to a current which has only one direction. … [1] [Total: 9]

9 marks

Mark scheme: 4 (a) rheostat/variable resistor AND control/vary/change/ limit current /resistance/power/voltage across heater B1 (b) (i) P = VI in any form OR (I=) P/V C1 1.25 A A1 (ii) (R =) V/I in any form words or numbers C1 (voltage across X =) 2.4 (V) OR 6 - 3.6 (V) C1 1.92 Ω e.c.f. from (b) (i) A1 (c) battery running down/going flat/energy of battery used up OR V or e.m.f. less OR more/increasing resistance (of heater) NOT resistance of X increases B1 (d) (i) transformer condone step-up OR potential divider/potentiometer NOT extras B1 (ii) diode OR rectifier OR L.E.D. NOT extras B1 [9] IGCSE – May/June 2011 0625 31

This question in 0625/31 May/June 2011

10 (a) A cathode-ray oscilloscope makes use of the process known as thermionic emission. Describe what happens during this process. … … … [1] (b) In the space below, draw a labelled diagram of a cathode-ray oscilloscope. Include in your diagram the tube, the cathode, the accelerating anode, the focusing anode and both X- and Y-plates. Do not attempt to show any external circuits. [3] (c) A cathode ray is a beam of electrons. Suggest one way of controlling the number of electrons in the beam. … … [1] (d) One cathode-ray tube has 5000 V between the accelerating anode and the cathode. The beam of electrons carries a total charge of 0.0095 C in 5.0 s. Calculate (i) the current caused by the beam, current = … [2] (ii) the energy transferred by the beam in 20 s. energy = … [2] [Total: 9] Question 11 is on the next page.

9 marks

Mark scheme: 10 (a) release of electrons due to heating/high temperature/heater B1 (b) X- and Y-plates labelled B1 anodes either order, labelled, either plates/cylinders with holes B1 closed tube of sensible shape AND cathode AND anode(s) AND X- & Y- plates, all three features in correct order labels not needed for last mark but if given must be correct B1 (c) change current in filament/cathode/heater IGNORE limit OR change temperature/heat/power/energy of filament/cathode/heater OR change cathode-anode p.d./voltage OR change charge/voltage of grid B1 (d) (i) (I=)Q/t in any form C1 0.0019 A OR 1.9 × 10-3 A OR 1.9 mA A1 (ii) (E=) VIt OR VQ in any form, words, symbols, numbers (accept t=5s) C1 190 J OR candidate’s I × 100 000 correctly evaluated A1 [9]

This question in 0625/31 May/June 2011

8 (a) What is meant by the electromotive force (e.m.f.) of an electric power supply? … … [2] (b) When connected to a 240 V supply, a desk lamp has a power rating of 60 W. Calculate (i) the current in the lamp, current = … [2] (ii) the resistance of the lamp’s filament. resistance = … [2] (c) A torch lamp is normally connected to a 3.0 V battery and carries a current of 0.25 A. The resistance of its filament is 12 Ω. The desk lamp in (b) and the torch lamp are connected in series. Students X and Y plan to connect the lamp combination to a 240 V supply. Student X says that the filament of the torch lamp will melt and the circuit will no longer work. Student Y says that both lamps will light up and stay on. Show, with a suitable calculation, whether student X or student Y is correct. … … [2] [Total: 8]

8 marks

Mark scheme: 8 (a) energy supplied / work done (per unit charge) to B1 drive charge round a (complete) circuit B1 OR p.d. / voltage across battery / power source B1 (b) (i) P = IV OR (I =) P/V OR (I =) 60/240 C1 = 0.25 A OR ¼ A A1 (ii) I = V/R OR other version OR (R = )V/I C1 OR (R = )240/0.25 OR P=V2/R or other version e.g. (R=) V2/P OR (R=) 2402/60 R= 960 Ω A1 (c) current in series circuit = 240 / 972 =0.247 A B1 current suits both bulbs, (so both light up so Y is correct) B1 OR p.d. across bulb A = 240 × (960/972) = 237 V p.d. across bulb B = 240 × 12/972 = 2.96 V B1 p.d. suits both bulbs, (so both light up so Y correct) B1 [8]

This question in 0625/32 May/June 2011

10 (a) In the space below, draw the symbol for an OR gate. [1] (b) Describe the action of an OR gate in terms of its inputs and outputs. … … … … … [2] (c) A car manufacturer wishes to install an alarm system in a 2-door car to inform the driver if either door is not properly closed. An OR gate is to be used in the construction of this system. Describe suitable input and output arrangements for the gate. … … … … … … [3] [Total: 6] Question 11 is on the next page.

6 marks

Mark scheme: 10 (a) correct symbol for OR gate B1 (b) output is low / zero / off if both inputs are low / zero / off B1 output is high / one / on if one input is high / one / on BUT this mark is not scored if candidate puts output low when both inputs high B1 (c) switches in doors are on if doors are open or vice versa B1 (switches in) doors provide inputs (to gate) B1 output (of gate) is connected to buzzer / warning light / alarm B1 [6] IGCSE – May/June 2011 0625 32

This question in 0625/32 May/June 2011

8 (a) What is meant by the electromotive force (e.m.f.) of an electric power supply? … … [2] (b) When connected to a 240 V supply, a desk lamp has a power rating of 60 W. Calculate (i) the current in the lamp, current = … [2] (ii) the resistance of the lamp’s filament. resistance = … [2] (c) A torch lamp is normally connected to a 3.0 V battery and carries a current of 0.25 A. The resistance of its filament is 12 Ω. The desk lamp in (b) and the torch lamp are connected in series. Students X and Y plan to connect the lamp combination to a 240 V supply. Student X says that the filament of the torch lamp will melt and the circuit will no longer work. Student Y says that both lamps will light up and stay on. Show, with a suitable calculation, whether student X or student Y is correct. … … [2] [Total: 8]

8 marks

Mark scheme: 8 (a) energy supplied / work done (per unit charge) to B1 drive charge round a (complete) circuit B1 OR p.d. / voltage across battery / power source B1 (b) (i) P = IV OR (I =) P/V OR (I =) 60/240 C1 = 0.25 A OR ¼ A A1 (ii) I = V/R OR other version OR (R = )V/I C1 OR (R = )240/0.25 OR P=V2/R or other version e.g. (R=) V2/P OR (R=) 2402/60 R= 960 Ω A1 (c) current in series circuit = 240 / 972 =0.247 A B1 current suits both bulbs, (so both light up so Y is correct) B1 OR p.d. across bulb A = 240 × (960/972) = 237 V p.d. across bulb B = 240 × 12/972 = 2.96 V B1 p.d. suits both bulbs, (so both light up so Y correct) B1 [8]

This question in 0625/33 May/June 2011

10 (a) In the space below, draw the symbol for an OR gate. [1] (b) Describe the action of an OR gate in terms of its inputs and outputs. … … … … … [2] (c) A car manufacturer wishes to install an alarm system in a 2-door car to inform the driver if either door is not properly closed. An OR gate is to be used in the construction of this system. Describe suitable input and output arrangements for the gate. … … … … … … [3] [Total: 6] Question 11 is on the next page.

6 marks

Mark scheme: 10 (a) correct symbol for OR gate B1 (b) output is low / zero / off if both inputs are low / zero / off B1 output is high / one / on if one input is high / one / on BUT this mark is not scored if candidate puts output low when both inputs high B1 (c) switches in doors are on if doors are open or vice versa B1 (switches in) doors provide inputs (to gate) B1 output (of gate) is connected to buzzer / warning light / alarm B1 [6] IGCSE – May/June 2011 0625 33

This question in 0625/33 May/June 2011

8 (a) In Fig. 8.1, a magnet is moving towards one end of a solenoid connected to a sensitive centre- zero meter. During this movement a current is induced in the solenoid. S N Fig. 8.1 Suggest three possible changes to the system in Fig. 8.1 that would increase the induced current. 1. … 2. … 3. … [3] (b) Fig. 8.2 shows a transformer. P is the primary coil. S is the secondary coil. The coils are wound on an iron core. P S Fig. 8.2 P has 200 turns and S has 800 turns. The e.m.f. induced across S is 24 V. The current in S is 0.50 A. The transformer operates with 100% efficiency. Calculate (i) the voltage of the supply to P, voltage = … [2] (ii) the current in P. current = … [2] [Total: 7]

7 marks

Mark scheme: 8 (a) any three from: use a strong(er) magnet increase the number of coils in the solenoid / turns of solenoid closer together move the magnet fast(er). place iron core in the solenoid use thick(er) wire / low(er) resistance wire for solenoid max B3 (b) (i) NP/NS = VP/VS OR 200/800 = VP/24 OR VP = NPVS/NS OR VP = 200 x 24/800 C1 6.0 V A1 (ii) IpVp = IsVs OR IpNp = IsNs OR IP = ISVS/VP OR IP = ISNS/NP OR IP = (0.5 x 24)/6 OR IP = (0.5 x 800)/200 C1 2(.0) A allow ecf from (b)(i) A1 [7]

This question in 0625/31 Oct/Nov 2011

10 (a) In Fig. 10.1, A is a 1000 resistor, C is a transistor, and D is a lamp. S is a 9 V supply. D A + S – C B Fig. 10.1 (i) Name the component labelled B. … [1] (ii) At 20 °C the resistance of B is 800 . At 100 °C the resistance of B is 25 . In terms of the p.d. across B, explain what happens in the circuit as the temperature varies from 20 °C to 100 °C. … … … … … … [4] (b) Suggest a practical use for this circuit. … … [1] [Total: 6]

6 marks

Mark scheme: 10 (a) (i) thermistor B1 (ii) lamp is ON at 20 oC / low temperature and OFF at 100 oC / high temperature B1 p.d. across B is high at 20 oC / low temperature B1 p.d. across B is low at 100 oC / high temperature B1 OR as temperature rises, p.d. across B falls (B2) transistor acts as a switch for the lamp at a certain temperature OR lamp is ON if there is current in base / collector OR potential of base is high OR lamp is OFF if there is no current in base / collector OR potential of base is too low B1 IGCSE – October/November 2011 0625 31 (b) to switch on a warning light when temperature (required for a process) becomes too low OR to switch off a warning light when temperature (required for a process) becomes high enough B1 [6] example (e.g. freezer or incubator) not needed, but if given, explanation required

This question in 0625/31 Oct/Nov 2011

11 Fig. 11.1 shows the main components of a cathode-ray oscilloscope. fluorescent screen electron heater beam cathode anode Y-plates X-plates vacuum system Fig. 11.1 (a) State the purpose of (i) the heater, … … (ii) the cathode, … … (iii) the anode system. … … … [4] (b) Without deflection, the electron beam produces a spot at the centre of the fluorescent screen. A deflection of the spot towards the top of the screen is required. (i) Describe how the Y-plates can be used to bring about this deflection. … … (ii) Fig. 11.2 shows the Y-plates. Fig. 11.2 On Fig. 11.2, sketch the pattern of the electric field produced between the plates. [4] [Total: 8]

8 marks

Mark scheme: 11 (a) (i) to heat the cathode / C B1 (ii) to emit electrons / to undergo thermionic emission (when heated) B1 (iii) to attract / accelerate electrons B1 to allow the electrons / beam to pass through to the screen / to focus the beam / to direct the beam / produce a straight beam / to fix the beam current B1 (b) (i) p.d. / voltage / battery / power supply applied between / across plates B1 upper plate positive and lower plate negative B1 (ii) sketch showing: straight vertical lines from top plate to bottom plate B1 arrows pointing downwards / from + to – B1 [8]

This question in 0625/31 Oct/Nov 2011

9 Fig. 9.1 shows a circuit containing a battery, three resistors and an ammeter. 2 Ω 1 Ω A 6 Ω Fig. 9.1 (a) (i) Write down the equation for the effective resistance Rp of two resistors of resistances R1 and R2 connected in parallel. (ii) Use this equation to calculate the effective resistance of the two resistors in parallel in Fig. 9.1. effective resistance = … [2] (b) A voltmeter is to be used to measure the potential difference across the resistors in parallel. (i) On Fig. 9.1, draw the voltmeter in position in the circuit, using the correct circuit symbol. (ii) The ammeter reads 1.6 A. Calculate the reading on the voltmeter. voltmeter reading = … [3] (c) State what happens to the ammeter reading if the 1 Ω resistor is replaced by a 3 Ω resistor. … … [1] [Total: 6]

6 marks

Mark scheme: 9 (a) (i) 1/Rp = 1/R1 + 1/R2 OR (Rp =) R1R2/(R1 + R2) in any form B1 (ii) 1.5 Ω B1 [2] (b) (i) correct position, allow across ammeter as well B1 (ii) use of V = IR in any form C1 2.4 V OR 1.6 × candidate’s Rp V A1 [3] (c) reduced accept current decreases B1 [1]

This question in 0625/32 Oct/Nov 2011

10 The circuit shown in Fig. 10.1 was designed by an electronics student to provide a warning, by sounding the buzzer, that there is light in a photographic darkroom at times when it is in use. buzzer + A 6 V logic – P C component gate Y switch X B R Q Fig. 10.1 When the darkroom is in use the switch is moved to position P. When it is not in use, the switch is in position Q. Depending upon the light level, the resistance of the light dependent resistor varies between much higher and much lower than the resistance of resistor R. (a) State what happens to the resistance of the light dependent resistor when the light level changes from dark to light. … … [1] (b) Write down whether the voltage level is high (logic 1) or low (logic 0) at the various points in the circuit in the following situations: (i) at A light in the darkroom, … dark in the darkroom, … (ii) at B switch in position P, … switch in position Q. … [2] (c) The output C of logic gate X is only high (logic 1) when both inputs A and B are high (logic 1). State which type of gate is logic gate X. … [1] (d) State the name of component Y. … [1] (e) Explain whether or not the student’s circuit achieves the aim of providing a warning that there is light in the darkroom when it is in use. … … … … [2] [Total: 7]

7 marks

Mark scheme: 10 (a) decreases / low / very low / zero B1 [1] (b) (i) ecf from (a), both answers must be consistent with candidate’s (a) B1 e.g. decreases / low / very low / zero increases / high / v. high / > 5V light high OR 1 light low OR 0 AND dark low OR 0 AND dark high OR 1 (ii) switch position P high OR 1 AND switch position Q low OR 0 B1 [2] (c) AND gate B1 [1] (d) transistor B1 [1] IGCSE – October/November 2011 0625 32 (e) any 2 of: (input) A high (input) B high C high transistor switches on/works M1 yes / it would work A1 [2]

This question in 0625/32 Oct/Nov 2011

7 Fig. 7.1 shows a circuit containing a 12 V power supply, some resistors and an ammeter whose resistance is so small that it may be ignored. 12 V 6 Ω A 3 Ω 2 Ω 4 Ω Fig. 7.1 (a) (i) Determine the potential difference across the 2 Ω resistor. potential difference = … [1] (ii) State the potential difference across the 3 Ω resistor. … [1] (b) Calculate the effective resistance of (i) the 2 Ω and 4 Ω resistors connected in series, resistance = … [1] (ii) the 3 Ω and 6 Ω resistors connected in parallel. resistance = … [2] (c) Calculate the reading on the ammeter. ammeter reading = … [2] (d) Without further calculation, state what happens, if anything, to the ammeter reading if (i) the 2 Ω resistor is shorted out with a thick piece of wire, … (ii) the thick piece of wire from (d)(i) and the 3 Ω resistor are both removed. … [2] [Total: 9]

9 marks

Mark scheme: 7 (a) (i) 4 V B1 (ii) 12 V B1 (b) (i) 6 Ω B1 (ii) 1/R = 1/3 + 1/6 OR (3 × 6)/(3 + 6) C1 2 Ω A1 (c) V/R OR 12/candidate’s (ii) C1 6 A ecf A1 (d) (i) stays same B1 (ii) decreases B1 [9]

This question in 0625/33 Oct/Nov 2011

10 Fig. 10.1 shows schematically a digital electronic circuit. A light sensor B relay and lamp heat sensor Fig. 10.1 (a) State the name of the logic gate (i) at A, … (ii) at B. … [2] (b) The light sensor has a “high” (logic 1) output in bright light and a “low” (logic 0) output when it is dark. The heat sensor has a “high” (logic 1) output when it is hot and a “low” (logic 0) output when it is cold. State the outputs of A and B when (i) it is bright and cold, output of A = … output of B = … (ii) it is dark and hot. output of A = … output of B = … [4] (c) Suggest why B is connected to a relay in order to light the lamp. … … [1] (d) Suggest a practical use for this circuit. … … … [1] [Total: 8]

8 marks

Mark scheme: 10 (a) (i) NOT B1 (ii) AND B1 IGCSE – October/November 2011 0625 33 (b) (i) low / 0 / off B1 low / 0 / off B1 (ii) high / 1 / on B1 high / 1 / on B1 (c) B cannot provide enough power/voltage/current to light lamp (IGNORE strength) B1 (d) security lamp OR intruder alarm OR burglar alarm with explanation OR beach lighting OR air freezer at indoor ski slope OR fridge alarm i.e. something that switches on when hot and dark (in a practical situation) B1 [8]

This question in 0625/33 Oct/Nov 2011

9 Fig. 9.1 shows the circuit that operates the two headlights and the two sidelights of a car. For Examiner’s A Use 1 2 3 12 V 4.0 1 4.0 1 12 1 12 1 Fig. 9.1 Two of the lamps have resistances of 4.0 Ω when lit. The other two lamps have resistances of 12 Ω when lit. Switch A can be connected to positions 1, 2 or 3. (a) State what happens when switch A is connected to (i) position 1, … (ii) position 2, … (iii) position 3. … [1] (b) (i) State the potential difference across each lamp when lit. potential difference = … [1] (ii) Calculate the current in each 12 Ω lamp when lit. current = … [2] (c) Show, with reasons for your answer, which type of lamp, 4.0 Ω or 12 Ω, has the higher power. … … … … [3] [Total: 7]

7 marks

Mark scheme: 9 (a) (i) all lamps off (ii) 12 Ω lamps (only) on B1 (iii) 4 Ω lamps (only) on (b) (i) 12 V B1 (ii) I = V/R in any form OR V/R OR 12/12 C1 1.0 A OR 1 A A1 e.c.f. from (b)(i) (c) current in 4 Ω lamp = 3 (A) (current in 12 Ω lamp is in (b)(ii)) C1 (P =) IV OR I 2R C1 (P =) 36 W for 4 Ω lamp; P = 12 W for 12 Ω lamp A1 e.c.f. from (b)(ii) OR (P =) V2/R (C1) (P =) 122/4 = 36 W for 4 Ω lamp OR 122/12 = 12 W for 12 Ω lamp (C1) (P =) 122/4 = 36 W for 4 Ω lamp AND 122/12 = 12 W for 12 Ω lamp (A1) OR (P =) V2/R (B1) Same V for all lamps (M1) 4 Ω lamp has higher power / 12 Ω has lower power (A1) [Total 7] IGCSE – May/June 2013 0625 31

This question in 0625/31 May/June 2013

7 The solar charger shown in Fig. 7.1 is used to charge portable electronic devices in a part of For the world without any other electricity supply. Examiner’s Use solar panels Fig. 7.1 The dimensions of each of the solar panels are 0.25 m × 0.20 m. The solar power incident on 1.0 m2 of flat ground in this part of the world is 260 W. (a) Calculate the total solar power incident on the two panels of the charger. solar power = … [2] (b) The output of the charger is 0.95 A at 20 V. Calculate the efficiency of the charger. efficiency = … [3] (c) Three devices A, B and C are connected together and then connected to the 20 V For charger. The potential difference (p.d.) across A is measured as 14 V, across B it is 14 V Examiner’s and across C it is 6 V. Use Complete Fig. 7.2 to show the arrangement of the devices connected to the charger. Draw devices B and C as similar boxes to the box shown for device A. output from charger 20 V device A Fig. 7.2 [2] (d) Two other devices, D and E, have resistances of 20 Ω and 30 Ω. Calculate the total resistance of D and E when they are connected in parallel. total resistance = … [2] [Total: 9]

9 marks

Mark scheme: 7 (a) (Pi =) 260 (× 2) × length × breadth (= 260 × 0.1), words, symbols or numbers C1 note: gets this mark if omits factor of 2 (Pi = 2 × 260 × 0.25 × 0.2 =) 26 W A1 [2] (b) (Po = 0.95 × 20 =) 19 (W) B1 efficiency = output (energy) / input (energy) accept power for energy E = candidate’s Po/candidate’s Pi evaluated (= 0.73 or 73%), accept fraction (19/26) C1 0.73% or bald 73 gets unit penalty A1 [3] (c) A OR B in series with C connected across 20 V M1 parallel combination of A and B only A1 [2] (d) 1 / R = 1 / R1 + 1 / R2 OR R = R1R2 / (R1 + R2) in any form OR R1R2 / (R1 + R2) C1 words, symbols or numbers 12 Ω A1 [2] [Total: 9]

This question in 0625/32 May/June 2013

8 Fig. 8.1 shows a small, uncharged copper sphere suspended from a nylon thread, and a For plastic rod being rubbed with a woollen cloth. Examiner’s Use nylon plastic rod thread woollen cloth copper sphere Fig. 8.1 The rod becomes negatively charged as it is rubbed. (a) Explain, in terms of electrons, why copper is a conductor but nylon is an insulator. … … … [2] (b) Describe how the negatively charged rod may be used to induce a positive charge on the copper sphere. … … … … [3] (c) The copper sphere is given a positive charge, as shown in Fig. 8.2. + Fig. 8.2 On Fig. 8.2, draw arrows to indicate the direction and pattern of the electric field that surrounds the positively charged sphere. [2] [Total: 7]

7 marks

Mark scheme: 8 (a) in copper/metals/conductors, electrons (free to move) B1 in nylon/insulators electrons fixed/not free (to move) B1 (b) (negatively charged nylon) rod near to sphere B1 earth/touch (with hand) the sphere B1 remove earth/hand (and remove rod) B1 (c) at least four equally spaced, radial lines from surface M1 at least one outward arrow AND none wrong A1 [7]

This question in 0625/33 May/June 2013

10 Fig. 10.1 is the symbol for a NAND gate with inputs A and B. For Examiner’s Use input A output input B Fig. 10.1 (a) Input A and input B can be set to 1 (high) or to 0 (low). Complete the table below to give the outputs for this NAND gate. input input output A B 0 0 0 1 1 0 1 1 [1] (b) The two inputs of the NAND gate are joined together and connected to an input C, as shown in Fig. 10.2. input C output Fig. 10.2 (i) Determine the output of this NAND gate when 1. input C is set to 0, output = … 2. input C is set to 1. output = … [1] (ii) State the name of the logic gate that behaves in the same way as the NAND gate in Fig. 10.2. … [1] (c) A circuit combines three NAND gates. For Examiner’s The inputs to the circuit are P and Q, as shown in Fig. 10.3. Use P R T S Q Fig. 10.3 Points R, S and T in the circuit are also labelled. Input P is set to 0 and input Q is set to 1. Determine the logic states (0 or 1) of points R, S and T. point R = … point S = … point T = … [2] [Total: 5] Turn over for Question 11

5 marks

Mark scheme: 10 (a) in order downwards: 1 1 1 0 c.a.o. B1 (b) (i) 1 AND 0 (e.c.f. from (b)(i)) B1 (ii) NOT (gate) (allow NOR (gate)) B1 (c) R = 1 AND S = 0 (e.c.f. from (b)(i)) B1 T = 1 B1 [5] IGCSE – May/June 2013 0625 33

This question in 0625/33 May/June 2013

9 (a) State the relationship between For Examiner’s (i) the resistance R and the length L of a wire of constant cross-sectional area, Use … (ii) the resistance R and the cross-sectional area A of a wire of constant length. … [1] (b) A 60 W filament lamp X is connected to a 230 V supply, as shown in Fig. 9.1. 230 V X Fig. 9.1 Calculate the current in the filament. current = … [2] (c) Lamp Y has a filament made of the same metal as the filament of lamp X in (b). For Examiner’s This filament has half the length and one-third of the cross-sectional area of the filament Use of X. Lamp Y is also connected to a 230 V supply. current in filament of Y Calculate the ratio Show your working. current in filament of X. ratio = … [4] [Total: 7]

7 marks

Mark scheme: 9 (a)(i)(ii) R ∝ L in words or symbols (ii) AND R ∝ 1 / A in words or symbols B1 (b) P = IV OR (I =) P / V OR 60 / 230 C1 0.26 A A1 IGCSE – October/November 2013 0625 31 (c) length change divides resistance by 2 / multiplies current by 2 C1 cross-section change multiplies resistance by 3 / divides current by 3 C1 (overall) resistance of Y is 3/2 times bigger / 3/2 × 885 Ω / 1327 Ω OR current in Y 2/3 of 0.26 A = 0.17 A C1 current in Y / Current in X = 2/3 A1 [Total: 7]

This question in 0625/31 Oct/Nov 2013

11 (a) Describe the action of For Examiner’s (i) a NOT gate, Use … [1] (ii) a thermistor. … [1] (b) Fig. 11.1 shows a circuit that switches on a warning lamp when the temperature in an oven falls below a set value. thermistor warning P lamp R Fig. 11.1 Explain, with reference to the components in the circuit and point P, (i) why the warning lamp is on when the temperature in the oven is below the set value, … … … … … … … [4] (ii) the effect of changing the resistance of R. … … [1] [Total: 7]

7 marks

Mark scheme: 11 (a) (i) input high / on / 1, output low / off / 0 input low / off / 0, output high / on / 1 OR reverses / inverts state of input OR output opposite to input B1 (a) (ii) resistance changes as temperature changes B1 (i) at low temperature resistance of thermistor is high OR when temperature falls resistance of thermistor rises B1 p.d. across thermistor is high OR p.d. across R is low B1 (voltage) input to gate is low B1 output of gate is high (and warning light is on) B1 (ii) changes the temperature / set value at which the lamp comes on B1 [Total: 7]

This question in 0625/31 Oct/Nov 2013

8 (a) A piece of wire has a resistance of 0.45 Ω. For Examiner’s Calculate the resistance of another piece of wire of the same material with a third of the Use length and half the cross-sectional area. resistance = … [3] (b) Fig. 8.1 shows a circuit with three resistors, a power supply and four voltmeters. power supply I1 V reading V1 1 1 I2 3 1 I3 I4 2 1 V V reading V2 reading V3 V reading V4 Fig. 8.1 (i) Calculate the combined resistance of the three resistors. For Examiner’s Use resistance = … [3] (ii) Write down two relationships for the currents in the circuit. [2] (iii) Write down two relationships for the voltmeter readings in the circuit. [2] [Total: 10]

10 marks

Mark scheme: 8 (a) (one third length so) one third R, accept any division by 3 C1 (half area so) twice R, accept any doubling, including divide by ½ C1 (resistance = 0.45 × 2/3) = 0.3(0) Ω accept 1 sig. fig. A1 [3] (b) (i) 1(Ω) and 3(Ω) used in correct parallel formula C1 2(Ω) added to candidate’s parallel resistance C1 2.7 or 2.8 or 2.75 Ω A1 [3] (ii) any 2 from: I1 = I4 OR I1 = I2 + I3 OR I4 = I2 + I3 OR other correct relevant equation/inequality e.g. I4 = 4I3, I4 > I3 B2 [2] (iii) any 2 from: V1 = V4 OR V1 = V2 + V3 OR V4 = V2 + V3 OR correct relevant inequality e.g. V1 > V3 B2 [2] [Total: 10]

This question in 0625/32 Oct/Nov 2013

10 (a) (i) Fig. 10.1 shows the symbol for a logic gate. For Examiner’s Use Fig. 10.1 Name this logic gate. … (ii) Draw the symbol for a NOR gate. [2] (b) (i) The two inputs of a NAND gate are both low (logic level 0). Write down the output state. … (ii) One input of a NAND gate is low (logic level 0) and the other input is high (logic level 1). Write down the output state. … [2] (c) A logic gate contains a number of components. Circle one of the following that is contained in a logic gate. thermistor transformer transistor transmitter [1] [Total: 5]

5 marks

Mark scheme: 10 (a) (i) AND gate B1 (ii) correct symbol must have 2 inputs, 1 output concave input side, somewhat pointed on output side with small circle B1 [2] (b) (i) HIGH / 1 B1 (ii) HIGH / 1 B1 [2] (c) transistor circled B1 [1] [Total: 5]

This question in 0625/32 Oct/Nov 2013

8 An a.c. power supply is connected in series with a metal-filament lamp. A cathode-ray For oscilloscope (c.r.o.) is in parallel with the lamp, as shown in Fig. 8.1. Examiner’s Use Fig. 8.2 is the trace seen on the c.r.o. screen. lamp cathode-ray power oscilloscope supply Fig. 8.1 Fig. 8.2 A diode is inserted in the circuit, as shown in Fig. 8.3. lamp cathode-ray power oscilloscope supply Fig. 8.3 Fig. 8.4 (a) (i) On Fig. 8.4, draw the shape of the trace now seen on the screen. [2] (ii) Suggest a device that uses a diode in this way. … [1] (b) State and explain the effect on the lamp of inserting the diode into the circuit. … … … [2] [Total: 5]

5 marks

Mark scheme: 8 (a) (i) half-wave rectified trace (ignore horizontal lines) M1 horizontal lines and wavelength same and amplitude same/slightly reduced (≥ ¾A0 by eye) A1 [2] (ii) rectifier or suitable device or produce d.c. (from a.c. for electronic circuits) (condone flashing lamp of some sort) B1 [1] (b) (lamp becomes) dimmer/less bright/flashes on and off B1 less (thermal)energy/heat/power or (thermal) energy etc. for less time or current becomes zero B1 [2] [Total: 5] IGCSE – October/November 2013 0625 33

This question in 0625/33 Oct/Nov 2013

9 The a.c. supply from a power station is connected to the primary coil of a transformer. The For secondary coil is connected to long-distance transmission cables. Examiner’s Use (a) The output voltage of the transformer is greater than the input voltage. Explain how a transformer produces this output voltage. … … … … … … [4] (b) There are energy losses in the transmission cables. (i) Explain why the energy losses become greater when the length of the transmission cables is greater. … … … [2] (ii) Discuss the advantages and disadvantages of using transmission cables of greater cross-sectional area. … … … [2] [Total: 8]

8 marks

Mark scheme: 9 (a) (alternating current causes alternating/changing) magnetic field (in core) B1 alternating/changing magnetic field in secondary coil B1 voltage/e.m.f. induced (in secondary coil) B1 more turns (on secondary) so greater output B1 [4] (b) (i) resistance increases (with/is proportional to length (of cable)) B1 (energy losses) due to resistance (of cables)/heating in cables/electrical working (in cables)/I2R B1 [2] (ii) reduced resistance or less heat loss B1 more metal or cables heavier or more pylons or more costly to construct B1 [2] [Total: 8]

This question in 0625/33 Oct/Nov 2013

9 In the circuit shown in Fig. 9.1, resistors can be connected between terminals P and Q. The e.m.f. of the battery is 6.0 V. 6.0 V A P Q Fig. 9.1 (a) Calculate the current shown by the ammeter when a 12.0 Ω resistor and a 4.0 Ω resistor are (i) connected in series between P and Q, current = … [2] (ii) connected in parallel between P and Q. current = … [3] (b) State the relationship between (i) the resistance R and the length l of a wire of constant cross-sectional area, … (ii) the resistance R and the cross-sectional area A of a wire of constant length. … [2] (c) The 12.0 Ω and 4.0 Ω resistors in (a) are wires of the same length and are made of the same alloy. cross-sectional area of 12.0 Ω resistor Calculate the ratio: cross-sectional area of 4.0 Ω resistor ratio = … [1] [Total: 8]

8 marks

Mark scheme: 9 (a) (i) (I =) V / R OR 6 / (12 + 4) OR 6 / 16 C1 0.38 A / 0.37 A A1 IGCSE – May/June 2014 0625 31 (ii) 1 / R = 1 / R1 + 1 / R2 OR (R =) R1 R2 / (R1 + R2) OR above with numbers substituted C1 R = 3 (Ω) C1 (I = 6 / 3 =) 2(.0) A A1 OR ALTERNATIVE METHOD: 6 / 12 (C1) + 6 / 4 (C1) 2(.0) A (A1) (b) (i) R ∝ l (in words or symbols) OR directly proportional OR e.g. R doubles when l doubles B1 (ii) R ∝1 / A (or with words) OR inversely proportional OR e.g. R doubles when A halves B1 (c) 4 / 12 OR 4:12 OR 1 / 3 OR 1:3 OR 0.33 B1 [Total: 8]

This question in 0625/31 May/June 2014

10 Fig. 10.1 shows a coil of wire rotating steadily in the magnetic field between the poles of a permanent magnet. The current generated in the coil is to pass through resistor R. rotation of coil coil N S A B C D R Fig. 10.1 (a) The apparatus in Fig. 10.1 is part of an a.c. generator. What is connected between the ends A and B of the coil and the connections C and D? … [1] (b) (i) On Fig. 10.2, sketch a graph to show the variation with time of the current through R. [1] current 0 time Fig. 10.2 (ii) On Fig. 10.2, show the time T corresponding to one complete rotation of the coil. [1] (iii) State two ways in which the graph would be different if the coil spins at a faster rate. 1. … 2. … [2] (c) Suggest what could be connected between C and R so that the current in R is always in the same direction. … [1] [Total: 6]

6 marks

Mark scheme: 10 (a) slip-rings (and brushes) B1 (b) (i) sinusoidal curve, any value at t = 0 B1 (ii) appropriate T value indicated on graph B1 (iii) smaller T / time of one cycle OR higher frequency B1 higher maximum current / greater amplitude / higher peaks / higher peak-to-peak B1 (c) diode / rectifier B1 [Total: 6]

This question in 0625/31 May/June 2014

8 Fig. 8.1 shows three cells each with e.m.f. 1.5 V connected in series. 1.5 V 1.5 V 1.5 V 4.0 1 1.0 1 1.0 1 Fig. 8.1 (a) Calculate the combined e.m.f. of the cells. e.m.f. = … [1] (b) Calculate the combined resistance of the three resistors shown in Fig. 8.1. resistance = … [2] (c) Calculate the current in the 4.0 Ω resistor in Fig. 8.1. current = … [3] (d) Calculate the combined e.m.f. of the cells if one cell is reversed. e.m.f. = … [1] [Total: 7]

7 marks

Mark scheme: 8 (a) 4.5 V ignore sign B1 (b) 1 / Rp = 1 / R1 + 1 / R2 OR (Rp =) R1R2 / (R1 + R2) words, symbols or numbers C1 R = (1 / (1 / 1 + 1 / 5)) = 0.83 Ω A1 (c) V= IR in any form OR V / R words, symbols or numbers C1 use of total e.m.f. as V AND series resistance as R OR 4 / 5 of total emf seen OR 1 / 6 of total current seen C1 (I = 4.5 / 5 =) 0.90 A accept 0.9 e.c.f. from (a) A1 (d) 1.5 V ignore sign B1 [Total: 7]

This question in 0625/32 May/June 2014

10 (a) Fig. 10.1 shows a digital logic circuit, not using the recognised symbols. AND gate input A D input B OR gate output E input C Fig. 10.1 Complete the table below to indicate the logic levels of points D and E in the circuit, when points A, B and C are at the logic levels indicated. 0 represents low or off. 1 represents high or on. A B C D E 0 0 0 0 0 1 1 1 1 [3] (b) Draw the recognised symbol for an AND gate. [1] (c) A NAND gate can be replaced by an AND gate and a NOT gate. Draw a diagram to show how the AND gate and the NOT gate should be connected. Label clearly the logic gates and any input or output. [2] [Total: 6]

6 marks

Mark scheme: 10 (a) row 1 0 0 accept low / off B1 row 2 0 1 accept low / off and high / on B1 row 3 1 1 accept high / on B1 IGCSE – May/June 2014 0625 32 (b) 2 wires to flat (input) side, 1 wire from curved (output) side do not accept pointed curved side or small circle B1 (c) NOT gate connected to output of AND gate accept labelled boxes for gates do not allow any extra gates or inputs M1 NOT gate correct way round A1 [Total: 6]

This question in 0625/32 May/June 2014

9 Fig. 9.1 represents two identical metal plates, positioned horizontally, one above the other in a vacuum. Fig. 9.1 A negative charge of 0.000 000 042 C (4.2 × 10−8 C) is transferred to the upper plate, leaving the lower plate with a positive charge of the same size. (a) On Fig. 9.1, draw the pattern of the electric field between the two plates and indicate the direction of the lines of force. [3] (b) (i) A conducting copper wire is used to connect the two plates and this leaves the plates uncharged. Charge flows in the wire for 0.000 000 035 s (3.5 × 10−8 s). Calculate the average current in the wire during this time. current = … [3] (ii) State, in terms of its atomic structure, why the copper wire is an electrical conductor. … … … [2] [Total: 8]

8 marks

Mark scheme: 9 (a) at least three vertical lines between the plates B1 equally spaced OR some curvature at the ends B1 at least one correct (upwards) arrow AND none wrong B1 (b) (i) (I=) Q / t OR 0.000 000 042 / 0.000 000 035 OR 4.2 × 10–8 / 3.5 × 10–8 C1 1.2 × 10n for any n C1 1.2 A A1 (ii) contains electrons C1 electrons are free to move A1 [Total: 8]

This question in 0625/33 May/June 2014

10 The electric circuit in a clothes dryer contains two heaters X and Y in parallel. Fig. 10.1 shows the circuit connected to a 230 V power supply. 230 V X Y Fig. 10.1 When both switches are closed, the current in X is 3.5 A. (a) Calculate the power developed in heater X. power = … [2] (b) The resistance of X is double that of Y. Determine the total resistance of X and Y in parallel. resistance = … [4] [Total: 6]

6 marks

Mark scheme: 10 (a) (P=)VI OR 230 × 3.5 C1 805 / 810 W A1 (b) (IY=)7.0 (A) alternative method: (RX=)V / I OR 230 / 3.5 OR 66 / 65.7(1429) C1 (ITot=)10.5 (A) alternative method: ( (RY=) 230 / 7.0 OR 66 / 2 OR 65.7(1429) / 2 OR 33 / 32.9 / 32.85714) C1 (R=)V / I OR 230 / 10.5 alternative method: (R=)R1R2 / (R1 + R2) OR 2159 / 98.57 OR 1 / R= 1 / R1 + 1 / R2 OR 1 / R= 1 / 65.7N1 / 32.9 C1 22 / 21.9(0476) Ω A1 [Total: 6]

This question in 0625/33 May/June 2014

12 Overhead power cables supply electrical power to a town that is a considerable distance from the power station. The voltage at which the power is transmitted in the cables is very much greater than the voltage at the power station and the voltage of the mains supply in the town. (a) Explain the advantage of transmitting electrical power at a very high voltage. … … … … … [3] (b) It is suggested that the resistance of the cables can be changed by doubling their diameter. (i) Explain the effect of this change on the resistance of the cables. … … … [2] (ii) Suggest one disadvantage of doubling the diameter of the cables. … … [1] [Total: 6]

6 marks

Mark scheme: 12 (a) (high voltage allows) low/less reduced current B1 (PR)I2R OR IV OR (ER)I2Rt OR IVt OR depends on current heating effect owtte B1 low / less / reduced heating effect / heat generated (allow lost) / more efficient / cheaper etc. (NOT with reduced resistance) B1 (b) (i) (cross-sectional) area 4× larger OR resistance inversely proportional to area OR smaller resistance C1 reduced to ¼ A1 (ii) cables heavier OR more / stronger pylons or more material in cable B1 [Total: 6]

This question in 0625/33 May/June 2014

8 A charger for a cellphone (mobile phone) is marked: input: a.c. 240 V, 50 Hz, 80 mA. output: d.c. 5.3 V, 500 mA. (a) State (i) the component in the charger that converts a.c. to d.c., … (ii) the quantity that has the value 50 Hz. … [2] (b) Calculate (i) the output power of the charger, output power = … [2] (ii) the energy transferred in the output circuit when the cellphone is charged for 1.5 hours. energy = … [2] (c) In the following list, underline the quantity that is stored in the battery of the cellphone. voltage current power energy [1] [Total: 7]

7 marks

Mark scheme: 8 (a) (i) rectifier / diode B1 (ii) frequency (of A.C. supply) B1 (b) (i) (P =) IV OR 0.5 × 5.3 OR 500 × 5.3 C1 2.6 W OR 2600 mW A1 (ii) (E =) Pt OR IVt OR 2.65 × 1.5 × 3600 OR 0.5 × 5.3 × 1.5 × 3600 C1 14000 J A1 (c) energy only underlined B1 [Total: 7]

This question in 0625/31 Oct/Nov 2014

10 (a) In a room in a house there are four electric lamps in parallel with each other, controlled by a single switch. With all the lamps working, one of the lamp filaments suddenly breaks. What, if anything happens to the remaining lamps? Explain your answer. … … … … [2] (b) Fig. 10.1 shows the circuit diagram for the lamp in another room. X and Y are 2-way switches. lamp 1 1 2 2 X Y Fig. 10.1 (i) Complete the table, by indicating whether the lamp is on or off for each of the switch positions. position of switch X position of switch Y state of lamp 1 1 1 2 2 1 2 2 [2] (ii) Explain why this arrangement of switches is useful. … … [1] [Total: 5]

5 marks

Mark scheme: 10 (a) (lamps) stay on / have same brightness as before / nothing happens B1 (lamps) still connected to supply / have same voltage as before / are connected in parallel B1 (b) (i) line 1: on line 2: off line 3: off line 4: on B2 deduct one mark for e.e.o.e. (ii) when either switch is operated, the state of the lamp changes. B1 [Total: 5]

This question in 0625/31 Oct/Nov 2014

8 (a) Fig. 8.1 shows two resistors X and Y in series. X Y I R 2R Fig. 8.1 Complete the table below, using only the symbols I and R, alone or in combination. resistor resistance current potential power difference X R I I2R Y 2R 2IR [3] (b) Fig. 8.2 represents the system used to transmit electricity from a power station to a factory. power line 750 A power 11 000 V factory station power line Fig. 8.2 The power station generates 11 000 V and supplies a current of 750 A. The total resistance of the power lines between the power station and the factory is 1.5 Ω. Calculate (i) the power output of the power station, power = … [1] (ii) the potential difference across the 1.5 Ω of the power lines, potential difference = … [1] (iii) the power supplied to the factory. power = … [3] [Total: 8]

8 marks

Mark scheme: 8 (a) one mark for each correct entry in table: B3 resistor resistance current potential power difference IR I 2I2R (b) (i) (P = IV = 750 × 11000 =) 8.3 × 106 W (8300 kW) B1 (ii) (V = IR =750 × 1.5 =) 1100 V B1 (iii) (voltage to factory = 11 000 – 1125 =) 9875 V C1 (power supplied to factory =) 9875 × 750 A1 7.4 × 106 W OR 7400 kW A1 OR power loss in cables = I 2R OR 7502 × 1.5 (C1) (=) 8.44 × 105 (W) (A1) (power to factory = 8.25 × 106 – 8.44 × 105 =) 7.4 × 106 W OR 7400 kW (A1) [Total: 8]

This question in 0625/32 Oct/Nov 2014

8 (a) Fig. 8.1 shows a 12.0 V battery connected to a resistor and a component X in series. 4.0 1 X 12.0 V Fig. 8.1 (i) Identify the component X. … [1] (ii) The p.d. across the 4.0 Ω resistor is 11.3 V. Calculate 1. the p.d. across component X, p.d. = … [1] 2. the current in the 4.0 Ω resistor. current = … [2] (b) The circuit in Fig. 8.1 is now modified as shown in Fig. 8.2. 8.0 1 4.0 1 12.0 V Fig. 8.2 (i) Calculate 1. the current in the 8.0 Ω resistor, current = … [1] 2. the current in the battery. current = … [1] (ii) The battery is now reversed. State the current in the battery. current = … [1] [Total: 7]

7 marks

Mark scheme: 8 (a) (i) diode B1 (ii) 1. 0.7 V B1 2. I = V÷R in any form OR (I =) V÷R OR 11.3÷4 C1 2.8 A A1 (b) (i) 1. (12÷8 =) 1.5 A B1 2. (1.5 + 2.825 =) 4.3 A ecf (a)(ii)2. and (b)(i)1. B1 (ii) 1.5 A ecf (b)(i)1. B1 [Total: 7]

This question in 0625/32 Feb/March 2015

9 In Fig. 9.1, a 12 V battery supplies a current I to a circuit. The circuit contains a thermistor and a 1000 Ω resistor in parallel, with a 500 Ω resistor in series. 12 V I 500 1 1000 1 Fig. 9.1 (a) At a certain temperature, the thermistor has a resistance of 1000 Ω. Calculate (i) the combined resistance of the thermistor and the 1000 Ω resistor, resistance = … [2] (ii) the current I, current = … [1] (iii) the potential difference across the 500 Ω resistor. potential difference = … [2] (b) The temperature of the thermistor is increased so that its resistance decreases. State the effect of this change in resistance on the current through the 500 Ω resistor. Explain your answer. … … … [2] [Total: 7]

7 marks

Mark scheme: 9 (a) (i) 1/R = 1/R1 + 1/R2 OR R = R1R2/(R1 + R2) OR with numbers C1 (R =) 500 Ω A1 (ii) I = (12 ÷ 1000) = 0.012 A ecf (i) B1 (iii) (V =) IR OR 0.012 × 500 OR 12 × 500 ÷ 1000 C1 = 6.0 V ecf (i)(ii) A1 (b) (more current in circuit so) current (in 500 Ω resistor) increases B1 resistance of parallel combination decreases OR total resistance (of circuit) decreases B1 [Total: 7]

This question in 0625/31 May/June 2015

10 Fig. 10.1 shows two parallel conducting plates connected to a very high voltage supply. + – + – conducting plate + – + – + – + – + – + – + – + – + – + – + – voltage supply Fig. 10.1 The left-hand plate is positively charged and the right-hand plate is negatively charged. (a) On Fig. 10.1, draw the electric field pattern produced between the charged plates. Use arrows to show the direction of the field. [2] (b) A light, conducting ball is suspended by an insulating string. Fig. 10.2 shows the ball in the middle of the gap between the plates. + – + – + – + – + – + – + – + – + – + – + – + – + – voltage supply Fig. 10.2 On Fig. 10.2, show the distribution of charge on the ball. [2] (c) The ball is displaced to the left and then oscillates backwards and forwards between the two plates. The ball touches a plate once every 0.05 s. Every time it touches a plate, a charge of 2.8 × 10−8 C (0.000 000 028 C) is transferred. Calculate the average current produced by the repeated transfer of charge. current = … [2] [Total: 6] Question 11 is on the next page.

6 marks

Mark scheme: 10 (a) (i) at least three horizontal, parallel lines evenly spaced (ignore edge effects) B1 arrows pointing left to right B1 (b) right hand half of ball has more + signs than – signs AND left hand half of ball has more – signs than + signs M1 equal numbers of + and – signs A1 (c) Q = I t in any form OR (I =) Q ÷ t OR 2.8 × 10–8 ÷ 0.05 C1 5.6 × 10–7 A OR C/s A1 [Total: 6]

This question in 0625/31 May/June 2015

8 Fig. 8.1 shows a circuit containing a battery of electromotive force (e.m.f.) 12 V and a heater of resistance 6.0 Ω. 12 V A 6.0 1 Fig. 8.1 (a) State what is meant by electromotive force (e.m.f.). … … [1] (b) (i) Calculate the current in the heater. current = … [2] (ii) State the name of the particles that flow through the heater. … [1] (iii) On Fig. 8.1, draw an arrow next to the heater symbol to show the direction of flow of these particles through the heater. [1] (c) Calculate the thermal energy produced in the heater in 10 minutes. thermal energy = … [2] [Total: 7]

7 marks

Mark scheme: 8 (a) energy transferred per coulomb/unit charge OR energy supplied in driving coulomb/unit charge around a circuit ACCEPT p.d./voltage across battery/power supply B1 (b) (i) V = IR in any form OR (I =) V ÷ R C1 2.0 A OR 2 A A1 (ii) electrons B1 (iii) arrow right to left by heater OR indication of clockwise B1 (c) (E =) VIt OR V 2t/R OR I 2Rt in any form C1 14 000 J A1

This question in 0625/32 May/June 2015

11 Fig. 11.1 shows the main components of a cathode-ray oscilloscope. fluorescent screen plate Y1 plate X2 heater beam P anode plate plate system Y2 X1 grid Fig. 11.1 (a) (i) State the function of component P. … … [1] (ii) Tick one box to complete the sentence correctly. A cathode-ray oscilloscope contains air at about five times normal atmospheric pressure. air at about normal atmospheric pressure. air at about one fifth of normal atmospheric pressure. a vacuum. neon gas. [1] (b) Fig. 11.2 shows the front view of the screen of the cathode-ray oscilloscope. B C A Fig. 11.2 With no voltage applied between the X-plates or between the Y-plates, the spot is at A. (i) Place two ticks in each of the blank columns of the table to describe the voltages across the plates when the spot is at points B and C. The column for the spot at A has been completed as an example. spot at A spot at B spot at C plate X1 at higher voltage than plate X2 plate X1 at lower voltage than plate X2 no voltage between X-plates ✓ plate Y1 at higher voltage than plate Y2 plate Y1 at lower voltage than plate Y2 no voltage between Y-plates ✓ [3] (ii) Explain your answers for the spot at point B. … … … … [1] [Total: 6]

6 marks

Mark scheme: 11 (a) (i) (function of cathode is) to emit/produce electrons B1 (ii) 4th box: vacuum B1 (b) (i) B: box 3 no voltage between X-plates B1 B: box 4 voltage plate Y1 > voltage plate Y2 B1 C: box 2 voltage plate X1 < voltage plate X2 AND box 4 voltage plate Y1 > than voltage plate Y2 B1 (ii) no voltage between X plates so no horizontal deflection AND beam attracted upwards to higher V / Y1 OR other correct argument B1

This question in 0625/32 May/June 2015

8 (a) A student determines the resistance of a length of aluminium wire. She connects the wire in series with a battery and a variable resistor. The circuit is shown in Fig. 8.1. aluminium wire Fig. 8.1 She knows that an ammeter and a voltmeter are needed in the circuit. (i) On Fig. 8.1, draw the circuit symbol for an ammeter connected in a suitable position. [1] (ii) A variable resistor is included so that the current in the circuit may be changed. Suggest an advantage of being able to change the current. … … [1] (b) Electricity is transmitted from a power station to a distant city using an aluminium cable of resistance 1.2 Ω. Power loss occurs because of the resistance of the cable. The current in the cable is 250 A. (i) Calculate the power loss in the cable. power loss = … [3] (ii) The aluminium cable is replaced with a new aluminium cable of the same length. The current remains at 250 A. The diameter of the new cable is double the diameter of the original cable. State and explain how the power loss is affected by this change. … … … [3] [Total: 8]

8 marks

Mark scheme: 8 (a) (i) ammeter symbol in series with wire B1 (ii) different results OR graph can be plotted OR to ensure wire does not overheat B1 (b) (i) (P = ) VI OR V = IR OR 250 × 1.2 OR 300 (V) C1 (P = ) I2 R OR 2502 × 1.2 OR 300 × 250 C1 75 000 W OR 75 kW A1 (ii) power loss reduced C1 resistance reduced C1 power lost decreases to a quarter OR (P =) 19 kW / 18.75 kW A1 [Total: 8]

This question in 0625/33 May/June 2015

8 A digital watch is powered by a 1.3 V cell. The cell supplies a current of 4.1 × 10–5 A (0.000041 A) for 1.6 × 107 s. Calculate (a) the charge that passes through the cell in this time, charge = … [2] (b) the resistance of the electrical circuit in the watch, resistance = … [2] (c) the output power of the cell. power = … [2] [Total: 6]

6 marks

Mark scheme: 8 (a) (Q =) It OR 4.1 x10–5 × 1.6 × 107 C1 = 660 C A1 (b) (R =) V / I OR 1.3 / 4.1 × 10–5 C1 = 32 000 Ω OR 32 kΩ A1 (c) 1st method: (P =) IV OR 4.1 × 10–5 × 1.3 OR 2nd method: (P =) I2R OR (4.1 × 10–5)2 × 32 000 OR 3rd method: (P =) V2 / R OR 1.32 / 32 000 OR 4th method: (P =) QV / t OR 660 × 1.3 / 1.6 × 107 C1 1st and 3rd methods: 5.3 × 10–5 W / 0.000053 W 2nd and 4th methods: 5.4 × 10–5 W / 0.000054 W A1 [Total: 6]

This question in 0625/31 Oct/Nov 2015

10 (a) Fig. 10.1 shows the symbol for a logic gate. Fig. 10.1 (i) State the name of this gate. … [1] (ii) On Fig. 10.1, label an input and an output. [1] (iii) In the space below, draw the symbol for a NAND gate. [1] (b) A very low frequency alternating voltage is applied between A and B in the circuit shown in Fig. 10.2. A B A centre-zero ammeter Fig. 10.2 On each diagram, draw a possible position of the indicator needle of the ammeter at the time in the cycle when (i) A is positive and B is negative, –1 0 +1 –2 +2 A (ii) there is no p.d. between A and B, –1 0 +1 –2 +2 A (iii) A is negative and B is positive. –1 0 +1 –2 +2 A [3] [Total: 6]

6 marks

Mark scheme: 10 (a) (i) OR (gate) B1 (ii) 1 input and 1 output labelled with words B1 (iii) correct symbol B1 (b) (i) needle not deflected B1 (ii) needle not deflected B1 (iii) needle deflected either way B1 [Total: 6]

This question in 0625/31 Oct/Nov 2015

9 (a) Fig. 9.1 shows the symbol for a logic gate. Fig. 9.1 (i) State the name of this gate. … (ii) On Fig. 9.1, clearly label an input and an output. [2] (b) In the space below, draw the symbol for a fuse. [1] (c) Fig. 9.2 shows a circuit. A 6 V B Fig. 9.2 Component A is not emitting light. It only emits light when the p.d. across it is greater than 1 V. (i) A change to the environment around component B causes component A to emit light. State the environmental change. … [1] (ii) Explain your answer to (i). … … … … [3] (d) The combined resistance of the two resistors shown in Fig. 9.3 is 4.0 Ω. 6.0 1 R Fig. 9.3 Calculate the resistance of resistor R. resistance of R = … [2] [Total: 9]

9 marks

Mark scheme: 9 (a) (i) NAND B1 (ii) output and one input correctly labelled B1 (b) rectangle with longitudinal line in middle third, no input or output wire required B1 (c) (i) temperature (decreases) B1 (ii) correctly relates change of resistance to change of temperature B1 voltage of mid-point (of potential divider) / left of LED increases OR higher V across thermistor B1 current flows through / enough V to light LED B1 (d) 1 / Rp = 1 / R1 + 1 / R2 or (Rp ) = R1R2 / (R1 + R2) C1 (R = 1 / (1 / 4 -1 / 6) =) 12 Ω A1 [Total: 9]

This question in 0625/32 Oct/Nov 2015

8 A metal sphere, mounted on an insulating plastic stand, is positively charged. (a) State the name of the unit in which electric charge is measured. … [1] (b) A smaller metal sphere, also mounted on an insulating plastic stand, is uncharged. This smaller sphere is moved close to the positively charged sphere. Fig. 8.1 shows the two spheres. positively charged sphere smaller sphere plastic stands Fig. 8.1 (i) On Fig. 8.1, draw the distribution of charge on the smaller sphere. [2] (ii) An earthed metal wire is touched against the smaller metal sphere. State and explain what happens to the charge on the smaller sphere. … … … [2] (c) Explain, in terms of their structures, why the metal wire is an electrical conductor but the plastic stand is an electrical insulator. … … … [2] [Total: 7]

7 marks

Mark scheme: 8 (a) coulomb B1 (b) (i) negative charge(s) on left AND positive charge(s) on right M1 equal number of positive and negative charges AND number of each ≤ 7 A1 (ii) electrons / negative charges flow from Earth / on to sphere (NOT protons / positive charges / positive electrons move) B1 total charge negative OR (some) protons / positive charges cancelled B1 (c) metal contains free (delocalised) electrons OR electrons can move about B1 electrons in plastic not free to move / fixed B1 [Total: 7]

This question in 0625/33 Oct/Nov 2015

9 (a) Place one tick in each row of the table to indicate one use of a thermistor and one use of a transistor. magnetic heat light field rectifier switch detector detector detector thermistor transistor [2] (b) In Fig. 9.1, lamp A is not glowing brightly. B 6 V A Fig. 9.1 Suggest and explain what could be done to component B to make lamp A glow brightly. … … … … … … [4] [Total: 6]

6 marks

Mark scheme: 9 (a) tick for thermistor under: heat detector B1 tick for transistor under: switch B1 (b) increase light intensity / brightness / illuminate B B1 resistance (of B) decreases cao B1 voltage at mid-point increases OR greater (share of) voltage M1 (more) current flows (through lamp) A1 [Total: 6]

This question in 0625/33 Oct/Nov 2015

10 The output of an a.c. generator in a power station is 5000 V. A transformer increases the voltage to 115 000 V before the electrical power is transmitted to a distant town. (a) State and explain, using a relevant equation, one advantage of transmitting electrical power at a high voltage. … … … … … [3] (b) The transformer contains two coils, the primary coil and the secondary coil. (i) State the other main component of a transformer and the material from which it is made. … … [1] (ii) State the component in the transformer to which the a.c. generator is connected. … … [1] (iii) There are 400 turns on the primary coil of the transformer. Calculate the number of turns on the secondary coil. number of turns = … [2] (c) Transformers within the town reduce the voltage to 230 V. Suggest one reason for this. … … [1] [Total: 8]

8 marks

Mark scheme: 10 (a) less power / energy lost OR heat generated (in cables) B1 smaller current B1 P = VI OR P = I2R B1 (b) (i) (laminated) iron core B1 (ii) (connected to) primary (coil) B1 (iii) (NS =) NPVS / VP OR 400 × 115 000 / 5 000 C1 9 200 (turns) A1 (c) less insulation needed OR safer OR devices designed for 230 V B1 [Total: 8]

This question in 0625/33 Oct/Nov 2015

11 (a) A student changes the current in a filament lamp. She measures the current and the potential difference (p.d.) across the lamp. Fig. 11.1 is an incomplete circuit diagram. Fig. 11.1 (i) On Fig. 11.1, complete the unfinished circuit symbols. [3] (ii) One pair of readings for the lamp is shown in the table. p.d. / V current /A 6.0 1.2 Calculate the resistance of the filament in the lamp for these readings. resistance of filament = … Ω [3] (iii) After many hours of use, the filament wire in a lamp becomes thinner. State the effect, if any, on the resistance of the lamp. … [1] (b)(i) Complete the circuit in Fig. 11.2 to show a battery connected to three lamps arranged in parallel. Fig. 11.2 [2] (ii) Describe two advantages of connecting these lamps in parallel with the battery. … … [2] [Total: 11]

11 marks

Mark scheme: 11 (a) (i) ammeter correct symbol in series with lamp B1 voltmeter correct symbol in parallel with lamp B1 lamp correct symbol B1 (ii) R = V / I in any form C1 6 ÷ 1.2 C1 5 (Ω) A1 (iii) (resistance) increases B1 (b) (i) 3 lamp symbols drawn B1 (lamps connected) in parallel with battery B1 (ii) any two from: B2 • lamps all have 6 V or full voltage (across them) • if one (lamp) breaks, others continue to operate / little / no effect on others • lamps can be switched on and off independently [Total: 11]

This question in 0625/32 Feb/March 2016

10 A student makes the circuit shown in Fig. 10.1 using a 12 V battery. 12 V X Y Fig. 10.1 (a) Complete the sentences about the circuit. Use words from the box. fixed resistor lamp light-dependent resistor parallel series thermistor (i) Components X and Y are connected in … [1] (ii) The component Y is a … [1] (b) Fig. 10.2 shows how the resistance of Y varies with temperature. 160 140 120 resistance / 1 100 80 60 40 20 0 0 5 10 15 20 25 30 35 40 45 50 temperature / °C Fig. 10.2 (i) Describe how the resistance of Y varies with temperature. … … … [2] (ii) The temperature of Y is 10 °C. The resistance of X is 20 Ω. Calculate the combined resistance of Y and X. resistance = … Ω [3] (iii) Calculate the current in the circuit. current = … A [3] [Total: 10]

10 marks

Mark scheme: 10(a)(i) series B1 10(a)(ii) thermistor B1 10(b)(i) resistance decreases as temp increases B1 at decreasing rate OR not proportional OR not linear B1 10(b)(ii) resistance of Y = 80 Ω C1 Rt = R1 + R2 in any form C1 100(Ω) A1 10(b)(iii) V = IR in any form C1 12 ÷ 100 OR 12 ÷ candidates (b)(ii) C1 0.12 (A) OR ECF from (b)(ii) A1 Total: 10

This question in 0625/31 May/June 2016

5 Fig. 5.1 shows two circuits, A and B. circuit A circuit B Fig. 5.1 Both circuits contain a 6 V power supply and two 6 V lamps. (a) State two advantages of circuit B compared to circuit A. … … … … [2] (b) Fig. 5.2 shows the energy input and outputs, in one second, for one electric lamp. useful energy output energy input 10.0 J wasted energy 8.2 J Fig. 5.2 (i) Calculate the useful energy output, in one second, of the lamp. useful energy output = … J [1] (ii) In the space below draw a labelled diagram, similar to Fig. 5.2, for a more efficient lamp. [1] (c) Electricity can be generated using wind turbines. Fig. 5.3 shows two wind turbines. Fig. 5.3 State two advantages and two disadvantages of using wind turbines, rather than fossil fuels, to generate electricity. advantages … … … … disadvantages … … … … [4] [Total: 8]

8 marks

Mark scheme: 5(a) any two from: lamps all have 6 V or full voltage (across them) OR lamps are brighter if one (lamp) breaks, little / no effect on other lamps can be switched on and off independently B2 5(b)(i) 10 – 8.2 OR 1.8 (J) B1 5(b)(ii) diagram indicating smaller proportion of energy wasted (e.g. greater useful energy output OR smaller wasted energy output OR smaller energy input for same output) B1 5(c) any two advantages from: renewable (energy source) does not contribute to global warming does not contribute to atmospheric pollution conserves fossil fuel reserves any two disadvantages from: not a reliable supply of electricity large area of land needed (for a wind farm) unsightly threat to birds large number needed to replace one power station infrastructure more expensive (per MW) than fossil fuel power stations needs a suitable (windy) location B2 B2 Total: 8

This question in 0625/32 May/June 2016

5 Fig. 5.1 shows two circuits, A and B. circuit A circuit B Fig. 5.1 Both circuits contain a 6 V power supply and two 6 V lamps. (a) State two advantages of circuit B compared to circuit A. … … … … [2] (b) Fig. 5.2 shows the energy input and outputs, in one second, for one electric lamp. useful energy output energy input 10.0 J wasted energy 8.2 J Fig. 5.2 (i) Calculate the useful energy output, in one second, of the lamp. useful energy output = … J [1] (ii) In the space below draw a labelled diagram, similar to Fig. 5.2, for a more efficient lamp. [1] (c) Electricity can be generated using wind turbines. Fig. 5.3 shows two wind turbines. Fig. 5.3 State two advantages and two disadvantages of using wind turbines, rather than fossil fuels, to generate electricity. advantages … … … … disadvantages … … … … [4] [Total: 8]

8 marks

Mark scheme: 5(a) any two from: lamps all have 6 V or full voltage (across them) OR lamps are brighter if one (lamp) breaks, little / no effect on other lamps can be switched on and off independently B2 5(b)(i) 10 – 8.2 OR 1.8 (J) B1 5(b)(ii) diagram indicating smaller proportion of energy wasted (e.g. greater useful energy output OR smaller wasted energy output OR smaller energy input for same output) B1 5(c) any two advantages from: renewable (energy source) does not contribute to global warming does not contribute to atmospheric pollution conserves fossil fuel reserves any two disadvantages from: not a reliable supply of electricity large area of land needed (for a wind farm) unsightly threat to birds large number needed to replace one power station infrastructure more expensive (per MW) than fossil fuel power stations needs a suitable (windy) location B2 B2 Total: 8

This question in 0625/33 May/June 2016

8 Fig. 8.1 shows two uncharged (neutral) plastic spheres. Each sphere is suspended by an insulating thread. insulating thread Fig. 8.1 (a) Suggest a material for the insulating threads. … [1] (b) The spheres can be given a charge. Three different experiments are carried out using the arrangements shown in Fig. 8.2. key negatively charged positively charged experiment 1 experiment 2 experiment 3 Fig. 8.2 For each experiment, describe the force, if any, between the spheres. experiment 1 … experiment 2 … experiment 3 … [3] (c) State and explain how one of the plastic spheres can be given a positive charge. … … … [2] [Total: 6]

6 marks

Mark scheme: 8(a) any named insulator, e.g. cotton, string etc. B1 8(b) 1 = attract B1 2 = repel B1 3 = repel B1 8(c) (sphere) is rubbed with a cloth B1 electrons move off (sphere) owtte B1 Total: 6

This question in 0625/33 Oct/Nov 2016

9 Fig. 9.1 shows the electric circuit for a fan heater. 24 V motor for fan P M heater Fig. 9.1 The fan blows air over the heater. The fan is driven by a motor connected to a 24 V d.c. supply. (a) Explain the difference between an a.c. supply and a d.c. supply. … … [1] (b) The circuit includes a component labelled P. (i) Name this component. … [1] (ii) Explain the function of this component in the circuit. … … [2] (c) (i) The heater has a resistance of 8.5 Ω and the potential difference across it is 24 V. Calculate the current in the heater. Include the unit. current = … [4] (ii) Suggest the rating of the fuse needed for the heater. … [1] (d) A different fan heater for use in a house is connected to a 110 V supply. This heater has a metal case. Explain the benefit of earthing the metal case. … … … … [1] [Total: 10]

10 marks

Mark scheme: 9(a) a.c. current changes direction OR d.c. one direction only B1 9(b)(i) variable resistor B1 9(b)(ii) changes the amount of current B1 changes speed of motor fan B1 9(c)(i) V = IR in any form C1 24/8.5 C1 2.82 A1 A OR amps B1 9(c)(ii) 5 (A) B1 9(d) protect user from electric shock B1 Total: 10

This question in 0625/33 Oct/Nov 2016

11 Fig. 11.1 represents part of an electricity transmission system. transmission lines X Y power station transformers house Fig. 11.1 (a) Transformers can be step-up or step-down. State the type of transformer shown at X and the type of transformer shown at Y. X … Y … [1] (b) A transformer has a primary coil of 24 000 turns, a secondary coil of 2000 turns and an input voltage of 132 000 V. Calculate the output voltage. output voltage = … V [2] (c) State two advantages of transmitting electricity at high voltages. 1. … 2. … [2] [Total: 5]

5 marks

Mark scheme: 11(a) X = step up AND Y = step down B1 11(b) Vp/Vs = Np/Ns OR Vs = 132 000 /(24 000/2000) OR turns ratio, 12 calculated C1 11 000 (V) A1 11(c) any two from: less heating OR less energy OR power wasted OR more efficient thinner wires OR cables fewer power stations lower current in cables transmit longer distances (without drop in power) B2 Total: 5

This question in 0625/33 Oct/Nov 2016

11 Fig. 11.1 shows a power supply in series with a resistance wire and a switch. power supply thin resistance wire Fig. 11.1 (a) When the switch is closed, energy is transferred from the power supply. Explain what happens to this energy. … … [2] (b) A student wants to determine the resistance of the wire. He adds components to the circuit shown in Fig. 11.1. (i) He measures the current in the circuit. State the name of the component that he uses. … [1] (ii) The student measures the potential difference (p.d.) across the resistance wire. On Fig. 11.1, draw the correct symbol for the component he uses and show how he connects it. [2] (iii) Fig. 11.2 shows the symbol for another component that the student adds to the circuit. Fig. 11.2 State the name and function of this component. name … function … … [2] [Total: 7]

7 marks

Mark scheme: 11(a) thermal B1 lost to surroundings/air owtte B1 11(b)(i) ammeter B1 11(b)(ii) correct symbol for voltmeter B1 connected in parallel with the resistance wire B1 11(b)(iii) variable resistor B1 varies/changes current/resistance/voltage (in resistance wire) B1 Total: 7

This question in 0625/31 May/June 2017

10 A student wants to investigate how the resistance of a light-dependent resistor (LDR) varies with the brightness of the light in the room. (a) To investigate this, the student connects the circuit shown in Fig. 10.1. V V Fig. 10.1 The student has made three errors. Identify the three errors in the student’s circuit. 1. … … 2. … … 3. … … [3] (b) The student corrects the errors. His results are shown in Fig. 10.2. 18 000 16 000 14 000 12 000 10 000 resistance of LDR / Ω 8000 6000 4000 2000 0 0 20 40 60 80 100 % of full brightness Fig. 10.2 (i) Use the information in Fig. 10.2 to describe how the brightness of the light in the room affects the resistance of the LDR. … … [1] (ii) The potential difference across the LDR is 8.0 V. Calculate the current in the LDR when the light is 60% of full brightness. current = … A [4] [Total: 8]

8 marks

Mark scheme: 10(a) in any order: cells/battery (connected) incorrectly voltmeter used instead of ammeter thermistor symbol used instead of LDR symbol B3 10(b)(i) resistance decreases as brightness increases B1 10(b)(ii) (resistance at 60% full brightness) = 2000 (ohms) B1 resistance = voltage ÷ current in any form e.g. I = V R C1 8.0 ÷ 2000 C1 4 × 10–3 (A) A1 Total: 8

This question in 0625/32 May/June 2017

8 A theatre has three coloured lamps. Fig. 8.1 shows the circuit for the coloured lamps. It is not complete. power supply Y X red green blue Fig. 8.1 (a) The circuit needs additional components so that • each lamp can be switched on and off separately, • the brightness of each lamp can be changed. Complete the circuit diagram in Fig. 8.1. [3] (b) Suggest the purpose of switch X. … [1] (c) State the name of component Y and describe how it works. name … description … … … … … [3] [Total: 7]

7 marks

Mark scheme: 8(a) circuit completed with 3 lamps in parallel B1 switch in each branch B1 variable resistor in each branch B1 8(b) switch all lights on/off B1 8(c) name: Fuse B1 if the current (in the fuse/circuit is) too large B1 (the wire in the fuse) melts B1 Total: 7

This question in 0625/33 May/June 2017

9 A student investigates how the resistance of a thermistor changes with temperature. Fig. 9.1 shows part of the circuit the student uses. power source A Fig. 9.1 (a) (i) On Fig. 9.1, label the thermistor. [1] (ii) The student measures the potential difference (p.d.) across the thermistor. On Fig. 9.1, draw a voltmeter symbol, correctly connected, to measure this potential difference. [2] (b) The student varies the temperature of the thermistor and measures the current in it. Some of the results are shown in the table. temperature of 20 40 60 80 thermistor / °C current in thermistor / A 0.005 0.010 0.040 (i) The potential difference across the thermistor is 6.0 V. Calculate the resistance of the thermistor when its temperature is 40 °C. resistance = … Ω [3] (ii) Describe and explain what happens to the current in the thermistor as the temperature of the thermistor rises. … … … [2] (iii) Suggest a value for the current in the thermistor at 80 °C. … A [1] (c) At a different temperature, the resistance of the thermistor is 300 Ω and the resistance of the variable resistor is 400 Ω. Calculate the value of their combined resistance. combined resistance = … Ω [1] [Total: 10]

10 marks

Mark scheme: 9(a)(i) Thermistor correctly identified B1 9(a)(ii) correct symbol for voltmeter B1 Voltmeter in parallel with thermistor B1 9(b)(i) V= IR C1 (R) = 6.0 ÷ 0.010 C1 600 (ohms or Ω) A1 9(b)(ii) Resistance is decreasing B1 So current will increase B1 9(b)(iii) Current greater than 0.04 (A) B1 9(c) 700 (ohms or Ω) B1

This question in 0625/31 Oct/Nov 2017

10 Fig. 10.1 shows a series circuit. fixed resistor 5.6 Ω A light-dependent resistor (LDR) Fig. 10.1 (a) In dim light, the resistance of the LDR is 20.0 Ω. (i) The resistance of the battery and ammeter can be ignored. Calculate the resistance of the circuit. resistance = … Ω [1] (ii) The current in the circuit is 0.23 A. Calculate the potential difference across the fixed resistor. potential difference (voltage) = … V [3] (b) A bright light shines on to the LDR. State and explain what happens to the current in the circuit. … … [2] [Total: 6]

6 marks

Mark scheme: 10(a)(i) B1 10(a)(ii) V = IR in any form C1 0.23 × 5.6 C1 1.29 OR 1.3 A1 10(b) resistance decreases B1 current increases B1

This question in 0625/32 Oct/Nov 2017

11 A student wants to find the resistance of a wire. He connects the circuit shown in Fig. 11.1. V wire A Fig. 11.1 (a) A teacher checks the circuit and identifies three errors. Using the components given in Fig. 11.1, carefully draw the correct circuit diagram in the space below. [3] (b) The student uses the correct circuit. The student finds that the current is 0.3 A when the potential difference across the wire is 2.7 V. Calculate the resistance of the wire. resistance = … Ω [3] (c) The student tests two other pieces of wire made of the same metal. He compares each resistance value with that of the first wire. State how the resistance compares with the first wire (i) for a wire that is longer, but of the same thickness, … [1] (ii) for a wire that is thicker, but of the same length. … [1] [Total: 8]

8 marks

Mark scheme: 11(a) ammeter in series B3 voltmeter across wire two cells correctly linked positive to negative 11(b) V = IR in any recognised form C1 R = 2.7 ÷ 0.3 C1 9 (Ω) A1 11(c) 1 higher / more B1 2. lower / less B1

This question in 0625/33 Oct/Nov 2017

10 Fig. 10.1 shows a circuit for determining the resistance of a component. A V Fig. 10.1 (a) On Fig. 10.1, label the fixed resistor, by writing the letter R. [1] (b) Two components in Fig. 10.1 measure electrical quantities. Identify the quantity that each component measures. Write each quantity and the unit of each quantity in the correct place in Table 10.1. component quantity unit A V Table 10.1 [4] (c) A student uses the circuit in Fig. 10.1 to determine the resistance of wires made from the same material. State how the resistance of a wire is related to its length and its diameter. length … … diameter … … [2] [Total: 7]

7 marks

Mark scheme: 10(a) resistor identified 1 10(b) quantity unit current NOT amps ignore ammeter A/amps/amperes 2 quantity unit potential difference or p.d. or emf V/volts ignore voltmeter 2 10(c) increasing (length) increases resistance owtte 1 increasing (diameter) decreases resistance owtte 1

This question in 0625/31 May/June 2018

11 Fig. 11.1 shows a vertical conductor passing through a horizontal piece of card. conductor card Fig. 11.1 (a) (i) On Fig. 11.1, draw a cell and a switch in series with the conductor to form a complete circuit. Use the correct circuit symbols. [2] (ii) A student sprinkles iron filings onto the card and closes the switch. There is a current in the conductor. Describe the pattern of the magnetic field seen. … … [2] (iii) The student reverses the direction of the current in the conductor. State the effect, if any, on the pattern he sees. … [1] (b) Describe an experiment to show that a force acts on a current-carrying conductor in a magnetic field. Show how to arrange the equipment. Include a diagram in your answer. … … … … … … … [4] [Total: 9]

9 marks

Mark scheme: 11(a)(i) cell and switch connected in series with any part of conductor (on Fig.11.1) 1 correct symbols used – (on Fig.11.1) 1 11(a)(ii) circular 1 around conductor/wire 1 11(a)(iii) no change/nothing 1 11(b) conductor/wire between the poles of a magnet 1 opposite poles facing each other 1 current in wire 1 wire moves/Flemings left hand rule indicated 1

This question in 0625/31 May/June 2018

9 (a) Fig. 9.1 shows a simple circuit. A 0.50 A V 12.0 Ω 6.0 Ω Fig. 9.1 (i) The current in the wires of the circuit is a flow of particles. Indicate the name of these particles. Tick one box. electrons atoms protons [1] (ii) Calculate the combined resistance of the two resistors. resistance = … Ω [1] (iii) Calculate the potential difference (p.d.) reading that would be shown on the voltmeter. potential difference (p.d.) = … V [3] (b) The circuit is changed. The two resistors are connected in parallel. Explain what happens, if anything, to the current reading on the ammeter. … … … [2] [Total: 7]

7 marks

Mark scheme: 9(a)(i) top box (electrons) ticked 1 9(a)(ii) 12 + 6 seen or 18 (Ω) 1 9(a)(iii) (V =) I × R 1 (V =) 0.50 × 18(.0) 1 (V =) 9.0 (V) ecf from (a)(ii) 1 9(b) (reading/current) increases 1 (because effective circuit) resistance decreases/resistors in parallel have less resistance 1

This question in 0625/32 May/June 2018

10 (a) Fig. 10.1 shows an electrical circuit. 12 V power supply A X R V Fig. 10.1 (i) State the name for the component labelled X and state its function in this circuit. name for component … function … … [2] (ii) Describe how the circuit shown in Fig. 10.1 could be used to find the resistance of the fixed resistor R. … … … … … [3] (b) An electrical heater has a resistance of 21.8 Ω when connected to a 240 V mains supply. (i) Calculate the current in the heater. current = … A [3] (ii) Suggest a rating for the fuse to be fitted to the mains plug for the heater. fuse rating = … A [1] [Total: 9]

9 marks

Mark scheme: 10(a)(i) variable resistor 1 change the current 1 10(a)(ii) Any three from: use low value of current measure (and record) current measure (and record) voltage repeat other values (of I and V) plot graph of pd against current (and find gradient) OR use V = I × R 3 10(b)(i) V = I × R in any form OR (I =) V ÷ R 1 240 ÷ 21.8 1 11.0 (A) 1 10(b)(ii) Answer in range 12 to 15 (A) 1

This question in 0625/33 May/June 2018

10 (a) A student does an experiment to determine the resistance of a fixed resistor, R. The student draws an incomplete diagram of the circuit, as shown in Fig. 10.1. open switch variable resistor R Fig. 10.1 (i) On Fig. 10.1, draw the missing circuit symbols. [3] (ii) Describe how the student could use the circuit to determine a reliable value for the resistance of R. … … … … … … … … [4] (b) Fig. 10.2 shows a 20 Ω resistor connected to a power supply. 0.4 A 20 Ω Fig. 10.2 A second 20 Ω resistor is connected in series with the first. State and explain how this affects the current in the circuit. … … … … [4] [Total: 11]

11 marks

Mark scheme: 10(a)(i) correct symbols for: ammeter B1 voltmeter B1 ammeter in series OR voltmeter in parallel B1 10(a)(ii) Any five from: close switch adjust / change variable resistor to give current in resistor / reading on ammeter measure / record (pair of) readings on ammeter and voltmeter description of any check for reliability idea of adjusting variable resistor to give range of readings plot a graph suitable spacing of readings e.g. every 0.05A or 0.1 A use of V= IR or R = V / I repeat AND calculate average (value for R) B4 10(b) (circuit) resistance increases B1 BUT (circuit) resistance doubles / becomes 40 Ω (award two marks as assumes previous (1st) marking point) B1 (current) decreases B1 BUT(current) halves / becomes 0.2 A (award two marks as assumes previous (3rd) marking point) B1

This question in 0625/31 Oct/Nov 2018

10 Fig. 10.1 shows a circuit used by a student to test a metal wire made of nichrome. ammeter X A 0.8 A ammeter Y A component Z V nichrome wire Fig. 10.1 (a) State the name of component Z. … [1] (b) The current reading on ammeter X is 0.8 A. State the reading on ammeter Y. … [1] (c) The current in the nichrome wire is 0.8 A. The potential difference (p.d.) across the nichrome wire is 4.5 V. Calculate the resistance of the nichrome wire. resistance = … Ω [3] (d) The student tests a different nichrome wire, which is thicker than the wire in (c), but of the same length. When testing this wire, the current in the wire is different from the value given in (c). State and explain the difference in current. … … … [2] [Total: 7]

7 marks

Mark scheme: 10(a) variable resistor or rheostat B1 10(b) 0.8 (A) B1 10(c) V = IR OR (R =) V ÷ I C1 4.5 ÷ 0.8 C1 5.6(25) A1 10(d) (current) increases OR larger B1 (as new/thicker wire has) less resistance B1

This question in 0625/32 Oct/Nov 2018

9 Fig. 9.1 shows a circuit with two lamps and three ammeters connected in series to a power supply. A1 A3 A2 Fig. 9.1 (a) The current shown on ammeter A1 is 0.6 A. Complete the table with the values for the current that would be shown on the other two ammeters. ammeter current / A A2 A3 [1] (b) The resistance of each lamp is 20 Ω. Determine the combined resistance of the lamps. resistance = … Ω [1] (c) The circuit is changed. The two lamps are connected in parallel. (i) Compare the current from the power supply with the current in each lamp. … … [1] (ii) Compare the resistance of one lamp in this circuit with the combined resistance of the two lamps connected in parallel. … … [1] (d) A different series circuit contains a 140 Ω fixed resistor. An ammeter in the circuit shows a current of 0.30 A. Calculate the potential difference (p.d.) across the resistor. State the unit. potential difference = … [4] [Total: 8]

8 marks

Mark scheme: 9(a) A2 = 0.6 A AND A3 = 0.6 A B1 9(b) 40 (Ω) B1 9(c)(i) current from source is higher than in each lamp or reverse argument B1 9(c)(ii) (combined) resistance of lamps in parallel is less / lower (than one lamp) B1 9(d) V = IR in any recognisable form C1 V = 0.30 × 140 C1 42 A1 V or volts B1

This question in 0625/33 Oct/Nov 2018

10 (a) State the name of the component represented by the symbol . Describe its purpose. name … purpose … [2] (b) Fig. 10.1 shows an electrical cooker hood used in some kitchens. fan driven by motor light Fig. 10.1 The cooker hood removes steam from the kitchen. It has a fan driven by a motor. It also has a lamp. Fig. 10.2 shows a simplified circuit diagram for the cooker hood. Y M T Z S Fig. 10.2 (i) State the type of electrical supply used by the cooker hood. … [1] (ii) Switch S is closed. Switch T is moved to position Y. State the name of any components that are switched on. … [1] (iii) Switch T is moved from position Y to position Z. Suggest how this change affects the motor. … [1] (c) Electrical appliances with metal cases can become dangerous if there is a fault. Suggest a hazard and describe a safety feature to reduce the danger. hazard … … safety feature … … [2] [Total: 7]

7 marks

Mark scheme: 10(a)(i) (name:) (fixed) resistor B1 (purpose:) (to) reduce current B1 10(b)(i) a.c. / alternating (current) B1 10(b)(ii) motor / fan AND lamp B1 10(b)(iii) (the motor / fan / it) slows (down) owtte B1 10(c) (hazard:) live wire touching case OR user gets electric shock / burns OR (electrical) fire OR overheating / wire gets hot B1 (safety feature:) case is earthed B1

This question in 0625/33 Oct/Nov 2018

9 Fig. 9.1 and Fig. 9.2 each show an electrical circuit. Each circuit has two lamps connected to an electrical supply. X Y … circuit … circuit Fig. 9.1 Fig. 9.2 (a) State the term used to describe each electrical circuit. Write the term under each circuit. [2] (b) State two disadvantages of the circuit in Fig. 9.2. 1. … 2. … [2] (c) Redraw the circuit in Fig. 9.1 with switches that will turn lamps X and Y on and off independently of each other. [2] (d) Fig. 9.3 shows another circuit. K W S1 S2 J Z Fig. 9.3 The lamps can be turned on and off using two different switches S1 and S2. Complete the table stating when the lamps are on or off. The first one has been done for you. switch positions lamps on or off S1 S2 K Z off K W J W J Z [3] [Total: 9]

9 marks

Mark scheme: 9(a) (Fig. 9.1 is a) parallel (circuit) B1 (Fig. 9.2 is a) series (circuit) B1 9(b) Any two from: lamps less bright if one lamp breaks the other does not light lamps cannot be switched independently B2 9(c) two correct switch symbols B1 switch on each branch B1 Question Answer Marks 9(d) (K W) on B1 (J W) off B1 (J Z) on B1

This question in 0625/32 Feb/March 2019

9 A student makes a circuit to switch on a 6.0 V lamp from two different switches X and Y. Fig. 9.1 shows the circuit. + 6.0 V – P R switch X switch Y Q S Fig. 9.1 (a) Switch X is in position P. State the position of switch Y for the lamp to be lit. … [1] (b) The current in the lamp is 0.50 A when the potential difference (p.d.) across the lamp is 6.0 V. Calculate the resistance of the lamp. Include the unit. resistance = … [4] (c) The student connects another 6.0 V lamp in parallel with the first lamp, as shown in Fig. 9.2. + 6.0 V – switch X switch Y Fig. 9.2 Give two advantages of connecting the lamps in parallel. … … … [2] [Total: 7]

7 marks

Mark scheme: 9(a) (position) R B1 9(b) V = IR in any form C1 (R =) 6.0 ÷ 0.5 OR 6.0 = 0.5 × R C1 (R=) 12 A1 Ω or ohms B1 9(c) both lamps have correct p.d. OR voltage (across them) B1 if one lamp fails the other is still lit B1

This question in 0625/31 May/June 2019

10 (a) A teacher demonstrates the action of a device. Fig. 10.1 shows the symbol for the device. Fig. 10.1 State the name of this device. … [1] (b) Fig. 10.2 shows another device being used in a circuit. The circuit contains a 6.0 V lamp. C + 12 V B – A sliding contact Fig. 10.2 (i) The sliding contact of this device is at position A, as shown in Fig. 10.2. Describe and explain the brightness of the lamp when the sliding contact is in this position. brightness of lamp … explanation … [2] (ii) The teacher moves the sliding contact from position A to position B. Describe and explain what happens to the brightness of the lamp. … … [2] (iii) The teacher moves the sliding contact from position B to position C. Suggest what happens to the lamp. … [1] [Total: 6]

6 marks

Mark scheme: 10(a) thermistor B1 10(b)(i) low (brightness) OR off M1 pd or voltage (across lamp) is zero or almost zero A1 10(b)(ii) (brightness / it) increases B1 p.d. / voltage (across lamp) increases B1 10(b)(iii) lamp blows / fuses (when p.d. too high) B1

This question in 0625/31 May/June 2019

10 Fig. 10.1 shows an incomplete circuit diagram for two identical lamps arranged in parallel. The circuit contains an ammeter and a voltmeter. Fig. 10.1 (a) On Fig. 10.1, complete the symbols for two lamps, an ammeter and a voltmeter positioned correctly. [5] (b) One of the lamps breaks. State the effect, if any, this has on the brightness of the other lamp. Explain your answer. effect … explanation … … [2] [Total: 7]

7 marks

Mark scheme: 10(a) ammeter symbol B1 ammeter in series (with power supply) B1 voltmeter symbol B1 voltmeter in parallel (with lamps/power supply) B1 two lamps in parallel B1 10(b) (brightness) stays the same B1 current (in working lamp) stays the same B1

This question in 0625/32 May/June 2019

9 (a) A student tests some materials to find which ones are electrical conductors. He uses the circuit in Fig. 9.1. A component B X Y Fig. 9.1 (i) State the name of component B. … [1] (ii) Describe how the student can use the circuit in Fig. 9.1 to test whether a material is an electrical conductor. … … … … [2] (iii) State which materials are electrical conductors. Put a tick in the box next to each material that is an electrical conductor. plastic copper rubber gold [1] (b) The student connects a resistor R, between X and Y. The student determines the resistance of the resistor. (i) Name the instrument he uses to measure the potential difference (p.d.) across resistor R. … [1] (ii) The current in resistor R is 0.2 A when the p.d. across the resistor is 6.0 V. Calculate the resistance of resistor R. resistance = … Ω [3] [Total: 8]

8 marks

Mark scheme: 9(a)(i) variable resistor B1 9(a)(ii) connect material in gap/between X and Y B1 if reading on ammeter material is a(n electrical) conductor B1 9(a)(iii) BOTH copper AND gold ticked i.e. 2nd and 4th boxes B1 9(b)(i) voltmeter B1 9(b)(ii) V = IR OR (R = ) V/I C1 = 6.0 ÷ 0. C1 = 30 (Ω) A1

This question in 0625/33 May/June 2019

10 A teacher is investigating the resistance of a lamp. Fig. 10.1 shows part of the circuit she uses. The circuit is incomplete. switch component X Fig. 10.1 (a) (i) To determine the resistance of the lamp, the teacher adds two meters to her circuit. On Fig. 10.1, draw circuit symbols to show each meter correctly connected in the circuit. [3] (ii) When the current in the lamp is 0.25 A, the potential difference (p.d.) across the lamp is 4.5 V. Calculate the resistance of the lamp. resistance = … Ω [3] (b) (i) State the name of component X. … [1] (ii) Describe and explain how the teacher uses component X to investigate the resistance of the lamp. … … … … [2] [Total: 9]

9 marks

Mark scheme: 10(a)(i) correct symbol for ammeter B1 correct symbol for voltmeter B1 ammeter in series and voltmeter in parallel with lamp B1 10(a)(ii) (R =) V ÷ I OR V = I × R in any form C1 (R = ) 4.5 ÷ 0.25 C1 18 ( Ω) A1 10(b)(i) variable resistor B1 10(b)(ii) (sliding contact moved to) change resistance (in circuit) B1 (and so) change current (in lamp) or p.d. (across lamp) B1

This question in 0625/31 Oct/Nov 2019

10 A circuit is made from two lamps, a cell and a switch, as shown in Fig. 10.1. Fig. 10.1 (a) (i) Draw the circuit symbol for a cell. [1] (ii) State the term used for the arrangement of lamps in the circuit in Fig. 10.1. … [1] (iii) The switch is closed and the lamps light. State the name of the charged particles that are flowing through the wires … [1] (b) Fig. 10.2 represents a different type of circuit. Fig. 10.2 (i) Compare Fig. 10.1 and Fig. 10.2. State two advantages of the type of circuit shown in Fig. 10.2 with the type of circuit shown in Fig. 10.1. 1. … 2. … [2] (ii) The potential difference across the power source in Fig. 10.2 is 3.0 V. The combined resistance of the two lamps is 12 Ω. Calculate the size of the current in the circuit. current = … A [3] [Total: 8]

8 marks

Mark scheme: 10(a)(i) cell symbol correctly drawn B1 10(a)(ii) series B1 10(a)(iii) electrons B1 10(b)(i) any two from: (both) lamps have correct / full potential difference if one lamp fails the other lamp still lights lamps can be switched (on/off)independently B2 10(b)(ii) V = IR or (I =) V ÷ R C1 3 ÷ 12 C1 0.25 (A) A1

This question in 0625/32 Oct/Nov 2019

10 Fig. 10.1 shows the symbol for an electrical component. Fig. 10.1 (a) State the name of the component shown in Fig. 10.1. … [1] (b) The resistance of the component shown in Fig. 10.1 varies with temperature. Fig. 10.2 shows a graph of resistance against temperature for the component. 5000 resistance / Ω 4000 3000 2000 1000 0 –10 10 30 50 70 90 110 Temperature / °C Fig. 10.2 (i) Use Fig. 10.2 to determine the resistance of the component at a temperature of 10 °C. … Ω [1] (ii) At another temperature, the resistance of the component is 800 Ω. Calculate the current in the component when it is connected to a 12.0 V supply. current = … A [3] [Total: 5]

5 marks

Mark scheme: 10(a) thermistor B1 10(b)(i) 2000 (Ω) B1 10(b)(ii) (I =) V ÷ R OR V = I × R in any form 12 ÷ 800 0.015 (A) C1 C1 A1

This question in 0625/33 Oct/Nov 2019

10 Fig. 10.1 shows an arrangement for making an electromagnet. 12 V A X core of electromagnet coil of thick copper wire Fig. 10.1 (a) (i) State a material which is suitable for the core of the electromagnet. … [1] (ii) State the name for component X in Fig. 10.1. … [1] (iii) Describe and explain how component X varies the strength of the electromagnet. … … … [2] (b) The switch is closed. The reading on the ammeter is 1.5 A. Calculate the resistance of the circuit. resistance = … Ω [3] [Total: 7]

7 marks

Mark scheme: 10(a)(i) (soft) iron (bar) B1 10(a)(ii) variable resistor B1 10(a)(iii) any two from: increasing the resistance (will) decrease the current (decreasing the current will) decrease the strength (of the electromagnet) B2 10(b) (R =) V ÷ I in any form C1 (R =) 12 ÷ 1.5 C1 (R =) 8.0 (Ω) A1

This question in 0625/32 Feb/March 2020

11 Fig. 11.1 shows lamps in series. Fig. 11.2 shows lamps in parallel. The lamps are all identical 6.0 V lamps. In each circuit there are three ammeters A1, A2 and A3. 6.0 V 6.0 V A1 A1 A3 A2 A2 A3 Fig. 11.1 Fig. 11.2 (a) (i) Compare the readings on ammeters A1, A2 and A3 in Fig. 11.1. … [1] (ii) Compare the readings on ammeters A1, A2 and A3 in Fig. 11.2. … [1] (iii) State two advantages of connecting the 6.0 V lamps in parallel with the 6.0 V battery, compared with connecting the lamps in series with the battery. 1. … … 2. … … [2] (b) Each lamp has a resistance of 12 Ω. (i) Determine the combined resistance of the two lamps connected in series. resistance = … Ω [1] (ii) Compare the resistance of one lamp with the combined resistance of the two lamps in parallel. … … [1] [Total: 6]

6 marks

Mark scheme: 11(a)(i) the ammeters all have the same reading B1 11(a)(ii) the reading on A1 is the biggest B1 11(a)(iii) lamps have normal brightness (in parallel) or brighter (than lamps in series) B1 If one lamp fails the other lamp is still lit B1 11(b)(i) 24 (Ω) B1 11(b)(ii) (resistance of one lamp / 12 (Ω)) is more (than the combined resistance (of lamps in parallel)) B1

This question in 0625/32 Feb/March 2020

10 (a) A student investigates the electrical resistance of some components. Fig. 10.1 shows an incomplete diagram of the circuit used by the student. Y Fig. 10.1 (i) State the term used for component Y. … [1] (ii) The student uses the circuit to measure the resistance of component Y. Complete the diagram in Fig. 10.1 by adding electrical symbols to show an ammeter and a voltmeter correctly connected to determine the resistance of component Y. [3] (b) Fig. 10.2 shows two resistors A and B. A B 5.0 Ω 7.0 Ω Fig. 10.2 (i) Resistor A and resistor B are connected in series. State the value of their combined resistance. … Ω [1] (ii) Resistor A and resistor B are connected in parallel. Compare the combined resistance when in parallel with the resistance of resistor A alone. … [1] [Total: 6]

6 marks

Mark scheme: 10(a)(i) thermistor B1 10(a)(ii) correct symbol for ammeter drawn B1 correct symbol for voltmeter drawn B1 both meters correctly positioned in circuit B1 10(b)(i) 12 (Ω) B1 10(b)(ii) smaller (than A) B1

This question in 0625/31 May/June 2020

11 A teacher uses a power supply in a metal case. The circuit for the power supply includes a fuse. (a) (i) Draw the electrical symbol for a fuse. [1] (ii) The metal case of the power supply is earthed. A fault occurs and a live wire touches the metal case. Explain how earthing the metal case protects the teacher. … … … … [3] (b) The power supply circuit includes a transformer. Its input voltage is 240 V. There are 960 turns on the input coil and 64 turns on the output coil. Calculate the output voltage of the transformer. output voltage = … V [3] [Total: 7]

7 marks

Mark scheme: 11(a)(i) correct symbol for fuse drawn B1 11(a)(ii) a large current flows to earth / in the live wire OR fuse is connected into live wire OR fuse contains thin / low melting point wire B1 Question Answer Marks any two from: current heats (fuse) wire fuse melts / blows (power supply circuit / metal case) is disconnected from mains (supply) B2 11(b) Vs/ Vp = Ns/ Np in any form C1 (Vs =) (64 × 240) ÷ 960 C1 16 (V) A1

This question in 0625/31 May/June 2020

10 A student connects three identical lamps J, K and L in a circuit, as shown in Fig. 10.1. Switch S1 is open and the current in ammeter A1 = 0.2 A. A1 K A2 J A3 L S1 Fig. 10.1 Use words from the box to complete the sentences. Each word may be used once, more than once, or not at all. the same increased decreased (a) The switch S1 in Fig. 10.1 is closed. State and explain the effect on the circuit. (i) The current in ammeter A1 is … because the resistance of the whole circuit is … . [2] (ii) The current in ammeter A2 is … . [1] (b) A student measures the potential difference (p.d.) across lamp J by using a voltmeter. On Fig. 10.1, draw the correct electrical symbol for the voltmeter with the correct connections. [2] (c) The p.d. across lamp J is 3.0 V and the current shown by ammeter A3 is 0.15 A. Calculate the resistance of lamp J. Include the unit in your answer. resistance of lamp J = … unit … [4] [Total: 9]

9 marks

Mark scheme: 10(a)(i) increased B1 decreased B1 10(a)(ii) the same B1 10(b) correct voltmeter symbol B1 in parallel with battery B1 10(c) R = V ÷ I in any form C1 3(.0) ÷ 0.15 C1 20 A1 Ω / ohms B1

This question in 0625/32 May/June 2020

10 A student determines the resistance of a piece of metal wire XY. Fig. 10.1 shows the wire connected in the circuit. variable A resistor X Y wire Fig. 10.1 (a) (i) The student measures the potential difference (p.d.) across the wire XY. On Fig. 10.1, show the voltmeter correctly connected. Use the correct symbol. [1] (ii) There is a current in the wire. State the name of the particles that flow through the wire. … [1] (iii) The student removes wire XY and replaces it with another wire CD. Wire CD is the same length and is made of the same material as wire XY, but thinner. State any difference between the current in wire CD and the current in wire XY. Explain your answer. … … … [2] (iv) State the unit used for the electromotive force (e.m.f.) of the battery. … [1] (b) (i) The resistance of wire CD is 8.7 Ω and the resistance of the variable resistor is 7.4 Ω. Determine the combined resistance of the wire CD and the variable resistor. resistance = … Ω [1] (ii) The current in the variable resistor is 0.40 A. State the current in wire CD. current = … A [1] [Total: 7]

7 marks

Mark scheme: 10(a)(i) correct symbol for voltmeter correctly connected B1 10(a)(ii) electrons B1 10(a)(iii) (current in CD) decreases B1 (because thinner wire / CD has) increased / bigger resistance B1 10(a)(iv) volt(s) B1 10(b)(i) 16.1 (Ω) B1 10(b)(ii) 0.40 (A) B1

This question in 0625/31 Oct/Nov 2020

8 (a) Fig. 8.1 shows the electrical symbols for some circuit components. Identify the circuit component for each electrical symbol. Draw a line from each electrical symbol to the name of the circuit component. electrical symbol circuit component fuse lamp buzzer thermistor Fig. 8.1 [3] (b) A student connects the circuit shown in Fig. 8.2. The value of the fixed resistor is 20 Ω. A 20 Ω Fig. 8.2 The switch is closed. The reading on the ammeter is 0.30 A. (i) Calculate the potential difference (p.d.) across the fixed resistor. potential difference = … V [3] (ii) State the name of the device for measuring potential difference. … [1] (iii) Show how the student connects the device stated in (b)(ii) to measure the p.d. across the fixed resistor. Draw the correct symbol and connections on Fig. 8.2. [1] [Total: 8]

8 marks

Mark scheme: 8(a) 1st box - thermistor B1 2nd box – fuse B1 3rd box -lamp B1 8(b)(i) V = I × R C1 (p.d. =) 0.30 × 20 C1 (p.d. =) 6.0 (V) A1 8(b)(ii) voltmeter B1 8(b)(iii) (voltmeter) in parallel with resistor or supply correct symbol for voltmeter B1

This question in 0625/33 Oct/Nov 2020

9 Fig. 9.1 shows an electric circuit. buzzer A V thermistor Fig. 9.1 (a) When the circuit is in a cool room, the voltmeter reading is 5.6 V and the ammeter reading is 0.040 A. Calculate the resistance of the thermistor. resistance of thermistor = … Ω [3] (b) The temperature of the thermistor increases and the buzzer turns on. State and explain how the increase in temperature affects the current in the thermistor. … … [2] (c) Suggest a possible use for the circuit shown in Fig. 9.1. … [1] [Total: 6]

6 marks

Mark scheme: 9(a) C1 5.6 ÷ 0.04 C1 140 (Ω) A1 9(b) (current in thermistor) increases B1 (because) resistance of thermistor decreases B1 9(c) fire / high temperature alarm / warning B1

This question in 0625/32 Feb/March 2021

10 (a) Fig. 10.1 shows a lamp and a resistor connected in a circuit. 4.0 V X A A Y 3.0Ω 5.0Ω Fig. 10.1 (i) Determine the combined resistance of the 3.0 Ω resistor and the 5.0 Ω lamp. combined resistance = … Ω [1] (ii) The reading on ammeter X is 0.50 A. State the reading on ammeter Y. reading on ammeter Y = … A [1] (b) In another circuit, the 3.0 Ω resistor and the 5.0 Ω lamp are connected in parallel, as shown in Fig. 10.2. 4.0 V X A A Y 3.0Ω 5.0Ω Fig. 10.2 The lamp and resistor have changed from a series to a parallel combination. State and explain the effect of this change on the current in ammeter X. … … … … [3] (c) The current in a different lamp is 0.40 A when the potential difference (p.d.) across the lamp is 6.0 V. Calculate the resistance of the lamp. resistance of lamp = … Ω [3] [Total: 8]

8 marks

Mark scheme: 10(a)(i) (3.0 + 5.0 =) 8.0 (Ω) B1 10(a)(ii) 0.5(0) (A) B1 10(b) (current/reading) increases B1 (because circuit) resistance decreases B1 (circuit)resistance becomes less than 3(.0) Ω OR less than smallest resistor (value) OR current/reading more than doubles B1 10(c) V= IR or (R =) V/I C1 6.0 ÷ 0.4 C1 15 (Ω) A1

This question in 0625/31 May/June 2021

9 (a) Fig. 9.1 shows an electric circuit. component X A V light-dependent resistor (LDR) Fig. 9.1 (i) The current in the metal wires of the circuit is a flow of particles. State the name of these particles. … [1] (ii) State the name of component X. … [1] (iii) The circuit is in a darkened room. The voltmeter reading is 5.5 V and the ammeter reading is 0.050 A. Calculate the resistance of the light-dependent resistor (LDR). resistance = … Ω [3] (b) The light in the room is switched on. The room becomes bright. State and explain how increasing the brightness of the light that falls on the LDR changes the current in the circuit. … … [2] [Total: 7]

7 marks

Mark scheme: 9(a)(i) 9(a)(ii) (component X is a) variable resistor B1 9(a)(iii) V= IR or (R =) V/I C1 5.5 ÷ 0.05 (0) C1 110 (Ω) A1 9(b) (current in circuit) increases B1 (because) resistance of LDR decreases B1

This question in 0625/32 May/June 2021

10 (a) Fig. 10.1 shows the circuit symbols for three electrical components. Draw a line from each circuit symbol to the correct electrical component. fuse heater variable resistor galvanometer thermistor Fig. 10.1 [3] (b) Fig. 10.2 shows a circuit consisting of a battery, a fixed resistor and an ammeter. A Fig. 10.2 (i) A voltmeter is connected in the circuit to measure the potential difference (p.d.) across the fixed resistor. By drawing on Fig. 10.2, show how the voltmeter is connected. Use the correct circuit symbol for the voltmeter. [2] (ii) The potential difference (p.d.) across the fixed resistor is 11.5 V. The reading on the ammeter is 0.25 A. Calculate the resistance of the fixed resistor. Include the unit in your answer. resistance = … unit … [4] [Total: 9]

9 marks

Mark scheme: 10(a) top to heater B1 middle to thermistor B1 bottom to galvanometer B1 10(b)(i) voltmeter symbol B1 in parallel with resistor / supply B1 Question Answer Marks 10(b)(ii) V = I × R in any form C1 11.5 ÷ 0.25 C1 46 A1 ohms / Ω B1

This question in 0625/33 May/June 2021

10 (a) A student plans to demonstrate the induction of an electromotive force (e.m.f.) in a wire. He has a length of wire, a sensitive centre‑reading galvanometer and a permanent magnet. (i) Describe how the student uses the equipment. … … [2] (ii) State two ways in which the student can increase the size of the induced e.m.f. 1 … 2 … [2] (b) Fig. 10.1 shows a d.c. motor. rotation of coil magnet coil current + – battery Fig. 10.1 (i) On Fig. 10.1, draw an arrow between the poles of the magnet to show the direction of the magnetic field. [1] (ii) State two ways of making the coil spin faster. 1 … 2 … [2] (iii) State one way of making the coil spin in the opposite direction. … [1] [Total: 8]

8 marks

Mark scheme: 10(a)(i) connect (both ends of) wire to galvanometer B1 move wire relative to magnet owtte B1 10(a)(ii) any two from: increase strength of magnet(ic field) OR strong(er) magnet turn wire into a coil owtte increase the speed (of relative motion) B2 10(b)(i) arrow drawn from N to S on Fig. 10.1 B1 10(b)(ii) any two from: increase (battery) voltage OR larger current in coil increase strength of magnet(ic) field OR strong(er) magnet increase number of turns in coil B2 10(b)(iii) reverse polarity of battery owtte OR reverse magnet(ic field) owtte B1

This question in 0625/31 Oct/Nov 2021

10 (a) Fig. 10.1 shows two resistors connected in series with a cell and three ammeters. reading = A1 A A reading = A3 reading = A2 A Fig. 10.1 (i) State the physical quantity that an ammeter measures. … [1] (ii) Indicate the correct statement about the readings A1, A2 and A3 on the ammeters in Fig. 10.1. Tick one box. A2 is greater than A1 A2 is less than A3 A1 is equal to A3 A1 is equal to (A2 + A3) [1] (b) (i) Draw a circuit diagram for a battery connected to two resistors in parallel. [2] (ii) State one advantage of connecting lamps in parallel. … [1] (c) Fig. 10.2 shows another circuit. component X Fig. 10.2 The circuit consists of a power supply, a lamp and component X. (i) Name component X in Fig. 10.2. … [1] (ii) Suggest one use of the circuit. … [1] (iii) Describe how to use component X and explain its effect on the circuit. … … … [2] [Total: 9]

9 marks

Mark scheme: 10(a)(i) (electric) current B1 10(a)(ii) tick in third box A1 is equal to A3 B1 10(b)(i) resistors in parallel B1 connected to battery AND correct circuit symbol for battery B1 10(b)(ii) same brightness / if one fails the rest are still lit / lamps can be switched off independently / same p.d. across owtte B1 10(c)(i) potential divider / potentiometer B1 10(c)(ii) dimmer / change light output / intensity B1 10(c)(iii) move the slider B1 varies p.d. (across lamp) B1

This question in 0625/32 Oct/Nov 2021

9 (a) The circuit diagrams in Fig. 9.1 and Fig. 9.2 each show two resistors connected to a battery. Fig. 9.1 shows two resistors connected in series. Fig. 9.2 shows two resistors connected in parallel. All the resistors have the same resistance. Ignore the resistance of the ammeters. 12 V 12 V A3 A1 A2 A4 A5 Fig. 9.1 Fig. 9.2 Compare the currents in the ammeters by completing the sentences. (i) The current in A1 is … the current in A2. [1] (ii) The current in A3 is … the current in A4. [1] (iii) The current in A4 is … the current in A5. [1] (iv) The current in A1 is … the current in A3. [1] (b) The lights in a room are connected in parallel with a power supply. State one advantage of connecting the lights in parallel. … [1] (c) The circuit diagram in Fig. 9.3 shows a resistor Q connected to a battery. A Q Fig. 9.3 The current in resistor Q is 0.048 A. The potential difference (p.d.) across resistor Q is 12 V. Calculate the resistance of resistor Q. Include the unit in your answer. resistance = … unit … [4] [Total: 9]

9 marks

Mark scheme: 9(a)(i) the same as B1 9(a)(ii) larger than B1 9(a)(iii) the same as B1 9(a)(iv) smaller than B1 9(b) same brightness / if one fails the rest are still lit / lamps can be switched off independently / same p.d. across owtte B1 9(c) V = I × R in any form (R =) V ÷ I C1 12 ÷ 0.048 C1 250 A1 Ω / ohms B1

This question in 0625/33 Oct/Nov 2021

10 (a) A student connects the circuit shown in Fig. 10.1. A LDR Fig. 10.1 (i) The student wants to determine the resistance of the light-dependent resistor (LDR). Draw on Fig. 10.1 to show how the student connects a voltmeter into the circuit. Use the correct symbol for the voltmeter. [2] (ii) The current in the LDR is 0.020 A when the potential difference (voltage) across the LDR is 5.4 V. Calculate the resistance of the LDR. resistance of LDR = … Ω [3] (b) When the student shines a light onto the LDR, its resistance is 150 Ω. The resistance of the variable resistor in the circuit is 180 Ω. Determine the combined resistance of the LDR and the variable resistor. combined resistance = … Ω [1] [Total: 6]

6 marks

Mark scheme: 10(a)(i) correct symbol for voltmeter B1 meter connected in parallel with LDR B1 10(a)(ii) 270 (Ω) A3 5.4 ÷ 0.02(0) (C2) V= IR or (R =) V/I (C1) 10(b) (150 + 180 =) 330 (Ω) B1

This question in 0625/32 Feb/March 2022

9 Fig. 9.1 shows an electric circuit which includes uninsulated resistance wire XY. A teacher shows some students how to complete the circuit by placing the contact C at various positions on the wire XY. 6.0 V d.c. A 8.0 Ω uninsulated resistance wire contact C X Y P Fig. 9.1 (a) The students place contact C at Y. They measure the current on the ammeter. Then they move the contact C along the wire from Y to X. State and explain the effect on the ammeter reading when they move the contact C from Y to X. … … [2] (b) Calculate the reading on the ammeter when contact C is at X. ammeter reading = … A [3] (c) The students move contact C to point P. The resistance of the wire between X and P is 20 Ω. Calculate the total resistance of the resistance wire between X and P and the fixed resistor. total resistance = … Ω [2] (d) The electric current in the circuit produces two effects. Place a tick (3) in the boxes next to these two effects. gravitational magnetic heating sound X-ray emissions [2] [Total: 9]

9 marks

Mark scheme: 9(a) (current/reading/it) increases B1 (because circuit) resistance decreases B1 9(b) 0.75 (A) A3 6(.0) ÷ 8(.0) (C2) V= IR or (I =) V/R (C1) 9(c) 28 () A2 (total resistance =) R1 + R2 OR 20 + 8(.0) (C1) 9(d) tick in 2nd box (magnetic) B1 tick in 3rd box (heating) B1

This question in 0625/31 May/June 2022

9 A student has a battery-operated torch. Fig. 9.1 shows the electrical components in the torch circuit. battery plastic case + brass switch connecting strip lamp Fig. 9.1 (a) Using standard symbols, draw a circuit diagram for the circuit in the torch. [4] (b) When the torch is switched on, the potential difference (p.d.) across the lamp is 1.4 V and the current in the lamp is 0.26 A. (i) State the current in the brass connecting strip. current = … A [1] (ii) Calculate the resistance of the lamp. resistance = … Ω [3] [Total: 8]

8 marks

Mark scheme: 9(a) correct symbol for battery B1 correct symbol for switch B1 correct symbol for lamp B1 all 3 components connected in series B1 9(b)(i) 0.26 (A) B1 9(b)(ii) 5.4 () A3 1.4 ÷ 0.26 (C2) V= IR or (R =) V/I (C1)

This question in 0625/32 May/June 2022

8 (a) The device in Fig. 8.1 is connected to a 240 V mains supply. The device produces a potential difference (p.d.) of 12 V between A and B. A 12 V lamp is connected between A and B. secondary coil A 240 V 12 V mains lamp supply B primary coil 8000 turns Fig. 8.1 (i) Calculate the number of turns on the secondary coil. Use information from Fig. 8.1. number of turns = … [3] (ii) State the name of the device shown in Fig. 8.1. … [1] (iii) The device includes two coils. State the material used for the coils. … [1] (b) The 12 V lamp is disconnected. Two 6.0 V lamps and a 12 V motor are connected between A and B. The p.d. across each lamp is 6.0 V and the p.d. across the motor is 12 V. Draw on Fig. 8.2 to show how to connect the lamps and the motor between A and B. A B Fig. 8.2 [3] [Total: 8]

8 marks

Mark scheme: 8(a)(i) 400 A3 (Ns = ) NP  VS/VP OR 8000  12/240 (C2) VP/VS = NP/NS in any form (C1) 8(a)(ii) (step-down) transformer B1 8(a)(iii) copper B1 8(b) motor connected between A and B B1 2 lamps in series connected between A and B A2 2 lamps in series (C1)

This question in 0625/33 May/June 2022

9 The circuit in Fig. 9.1 shows two resistors, a battery, a voltmeter and a switch connected by metal wires. 12 V A B 10Ω 20Ω V Fig. 9.1 (a) State a quantity that a voltmeter measures. … [1] (b) The switch is closed. There is a current in the circuit. (i) State the name of the type of particle that flows in the metal wires. … [1] (ii) State the name of an instrument that measures electric current. … [1] (c) The reading on the voltmeter is 4.0 V. (i) Calculate the current in the 10 Ω resistor. current = … A [3] (ii) Determine the current in the 20 Ω resistor. current = … A [1] (iii) The 10 Ω resistor is replaced by a 15 Ω resistor and the 20 Ω resistor is also replaced by a 15 Ω resistor. State the effect, if any, on the current in the circuit. Explain your answer. … … [2] [Total: 9]

9 marks

Mark scheme: 9(a) electromotive force/e. m. f./ potential difference/p. d./ voltage B1 Question Answer Marks 9(b)(i) electron(s) B1 9(b)(ii) ammeter B1 9(c)(i) 0.4(0) (A) A3 4(.0) ÷ 10 (C2) (I = ) V ÷ R in any form (C1) 9(c)(ii) 0.4(0) (A) OR same as (c)(i) B1 9(c)(iii) no change/same M1 resultant/total/combined resistance does not change A1

This question in 0625/33 May/June 2022

8 Fig. 8.1 shows an electric circuit set up by a student. switch ammeter metal wire battery lamp 15 Ω resistor Fig. 8.1 (a) Using standard symbols, draw a circuit diagram for the student’s circuit. [4] (b) When the switch is closed there is a current in the circuit. State the name of the particles flowing in the metal wire. … [1] (c) The current in the 15 Ω resistor in Fig. 8.1 is 0.40 A when the switch is closed. Calculate the potential difference (p.d.) across the 15 Ω resistor. p.d. across resistor = … V [3] [Total: 8]

8 marks

Mark scheme: 8(a) 5 correct symbols for 3 marks B3 3 or 4 correct symbols for 2 marks 1 or 2 correct symbols for 1 mark any from: • correct symbol for battery • correct symbol for ammeter • correct symbol for lamp • correct symbol for fixed resistor • correct symbol for switch. all components drawn connected in a series circuit B1 8(b) electrons B1 8(c) 6(.0) (V) A3 0.40  15 C2 (V =) I  R OR R = V / I C1

This question in 0625/31 Oct/Nov 2022

8 A student uses the circuit in Fig. 8.1 to find the resistance of a piece of iron wire. variable battery resistor ammeter voltmeter A B iron wire rule Fig. 8.1 (a) Complete Fig. 8.2 to show the circuit diagram for the arrangement shown in Fig. 8.1. The piece of iron wire is shown as the thicker line between the points A and B. 4.5 V A B [3] Fig. 8.2 (b) The reading on the voltmeter is 1.56 V. The reading on the ammeter is 0.112 A. Calculate the resistance of the iron wire. Include the unit in your answer. resistance = … unit … [4] [Total: 7]

7 marks

Mark scheme: 8(a) ammeter, battery and test wire in complete series circuit B1 voltmeter in parallel with AB B1 correct circuit symbols for ammeter AND voltmeter B1 8(b) 14 A3 1.56 ÷ 0.112 (C2) (R =) V ÷ I in any form OR V = I  R (C1)  / ohm(s) B1

This question in 0625/32 Oct/Nov 2022

9 Fig. 9.1 shows a series circuit. Two of the components in the circuit are labelled. power supply lamp Fig. 9.1 (a) State the name of two other components in the circuit. 1 … 2 … [2] (b) The current in the lamp is 0.40 A. The potential difference (p.d.) across the lamp is 6.0 V. Calculate the power dissipated in the lamp. power = … W [3] (c) Draw on Fig. 9.1 to show a lamp connected in parallel with the lamp in the circuit. Use the correct symbol. [1] [Total: 6]

6 marks

Mark scheme: 9(a) any two from:  switch  ammeter  variable resistor B2 9(b) (power =) 2.4 (W) A3 (power =) 0.4(0)  6(.0) (C2) (power =) I  V (C1) 9(c) lamp symbol drawn in parallel with lamp in circuit B1

This question in 0625/31 May/June 2023

8 A student uses the circuit in Fig. 8.1 to measure the resistance of the heater in the circuit. variable resistor heater Fig. 8.1 (a) The symbols for the meters in Fig. 8.1 are incomplete. Complete the symbols for the two meters by writing in the circles in Fig. 8.1. [2] (b) The current in the heater is 1.4 A and the potential difference (p.d.) across the heater is 8.0 V. Calculate the resistance of the heater. resistance = … Ω [3] (c) The heater is switched on for 30 s. The current in the heater is 1.4 A and the p.d. across it is 8.0 V. Calculate the electrical energy transferred by the heater during the 30 s. energy transferred = … J [3] [Total: 8]

8 marks

Mark scheme: 8(a) ammeter symbol correct B1 voltmeter symbol correct B1 8(b) (R =) 5.7 () A3 (R =) 8(.0) ÷ 1.4 (C2) V = IR in any form OR (R =) V ÷ I (C1) 8(c) (E =) 340 (J) A3 (E =) 8(.0)  1.4  30 (C2) (E =) V I t (C1)

This question in 0625/32 May/June 2023

8 (a) Fig. 8.1 shows the electrical symbols for some circuit components. Draw a line from each electrical symbol to the name of the circuit component it represents. electrical symbol circuit component fuse lamp heater thermistor Fig. 8.1 [3] (b) Fig. 8.2 shows a circuit including a battery, a fixed resistor R and an ammeter. A R Fig. 8.2 The reading on the ammeter is 0.38 A. The potential difference across the fixed resistor R is 12 V. (i) Calculate the resistance of the fixed resistor R. resistance = … Ω [3] (ii) Calculate the electrical power transferred in the fixed resistor R. Include the unit. power transferred = … unit … [4] [Total: 10]

10 marks

Mark scheme: 8(a) B1 B1 B1 8(b)(i) (R =) V ÷ I in any form C1 12 ÷ 0.38 C1 32 () A1 8(b)(ii) (P =) IV in any form C1 12  0.38 C1 4.6 A1 W OR watts B1

This question in 0625/33 May/June 2023

6 Fig. 6.1 shows four wind turbines. air ground Fig. 6.1 (a) Describe how a wind turbine generates electrical power. … … … [3] (b) The electrical power output of a wind turbine is 624 kW. The output current is 520 A. Calculate the output voltage of the wind turbine. output voltage = … V [4] (c) For transmission, the output voltage is increased to 132 kV. State two advantages of transmitting electrical power at high voltage. 1 … 2 … [2] [Total: 9]

9 marks

Mark scheme: 6(a) KE of wind B1 rotates / turns / spins turbine OR blades B1 (turbine) turns / spins / rotates generator B1 6(b) (output voltage =) 1200 (V) OR 1.2 kV A4 (V =) 624 000 ÷ 520 (C3) conversion: 624 kW = 624 000 (W) (C1) power = I  V OR (V =) P ÷ I (C1) 6(c) any two from: B2 greater efficiency as lower current (is used) (so) reduces power / energy losses thinner cables can be used (so reducing costs) OR pylons further apart idea of increased distance of transmission (of electrical power)

This question in 0625/31 Oct/Nov 2023

9 A student investigates an electric circuit. Fig. 9.1 shows the student’s circuit. 6.0 V A heater Fig. 9.1 (a) (i) Describe the purpose of the variable resistor in Fig. 9.1. … … [1] (ii) The student uses cells with an electromotive force (e.m.f.) of 1.5 V. Determine the number of cells needed for the 6.0 V battery in Fig. 9.1. number of cells needed = … [1] (iii) The student connects another component to measure the potential difference (p.d.) across the heater. On Fig. 9.1, draw the electrical symbol and connections for this component. [2] (b) The p.d. across the heater is 4.0 V. The current in the heater is 1.6 A. Calculate the energy transferred electrically by the heater in 40 s. energy transferred = … J [3] [Total: 7]

7 marks

Mark scheme: 9(a)(i) (to) change / control current (in circuit / heater) B1 OR change / control p.d. voltage (across heater) 9(a)(ii) (6.0 ÷ 1.5 =) 4 (cells) B1 9(a)(iii) symbol for voltmeter seen or used B1 connected in parallel with heater B1 9(b) (E =) 260 (J) A3 (E =) 1.6  40  4.0 (C2) (E =) I  t  V OR P = I  V AND (E =) P  t (C1)

This question in 0625/31 Oct/Nov 2023

7 Two identical resistors, R1 and R2, are connected to a 24 V battery, as shown in Fig. 7.1. 24 V R1 R2 Fig. 7.1 The value of each resistor is 50 Ω. (a) Calculate the combined resistance of R1 and R2 when they are connected as shown in Fig. 7.1. combined resistance = … Ω [1] (b) Show that the current in the circuit is approximately 0.25 A. [3] (c) Determine the potential difference (p.d.) across R1. p.d. = … V [1] (d) Calculate the power transferred in R1. power = … W [3] (e) A student connects R1, R2 and the battery to make a different circuit. The resistors R1 and R2 are connected so their combined resistance is as small as possible. Draw a circuit diagram to show how R1 and R2 are connected to the battery. [1] [Total: 9]

9 marks

Mark scheme: 7(a) 100 () B1 7(b) 0.24 (A) B1 24 / 100 (current =) voltage / resistance B1 Need to see zone (a) B1 7(c) 12 (V) B1 7(d) 3(.0) (W) OR 2.9 (W) A3 0.25  12 (C2) (power =) current  voltage OR (P =) V × I (C1) 7(e) (two) resistors in parallel B1

This question in 0625/33 Oct/Nov 2023

9 A student connects the electrical circuit shown in Fig. 9.1. switch ammeter metal wire battery lamp thermistor Fig. 9.1 (a) Fig. 9.2 shows part of the circuit diagram for the circuit in Fig. 9.1. Fig. 9.2 Complete the circuit diagram in Fig. 9.2 to represent the circuit in Fig. 9.1. Use standard electrical symbols. [4] (b) The potential difference across the lamp is 5.4 V and the current in the lamp is 0.20 A. (i) Calculate the resistance of the lamp. resistance = … Ω [3] (ii) The lamp is switched on for 30 s. Calculate the energy transferred in the lamp during this time. energy transferred = … J [3] (c) The student increases the temperature of the thermistor. State and explain what happens to the current in the circuit. … … [2] [Total: 12]

12 marks

Mark scheme: 9(a) correct symbol for: ammeter B1 lamp B1 thermistor B1 symbols connected in series circuit B1 9(b)(i) 27 () A3 5.4 ÷ 0.2(0) (C2) (R=) V ÷ I OR V = I R or in any form (C1) 9(b)(ii) 32 (J) A3 (E =) 5.4  0.2  30 (C2) (E=) VItOR P  t OR I2  R  t (C1) 9(c) current increases B1 (because) resistance (of thermistor) decreases B1

This question in 0625/32 Feb/March 2024

7 A battery, a lamp L, a fixed resistor R and a switch S are connected as shown in Fig. 7.1. 6.0 V R L S Fig. 7.1 (a) The potential difference (p.d.) across lamp L is 4.8 V and the current in lamp L is 0.40 A. Calculate the resistance of lamp L. resistance = … Ω [3] (b) State and explain how closing switch S affects the brightness of lamp L. … … … … [3] [Total: 6]

6 marks

Mark scheme: 7(a) A3 4.8 / 0.4 (C2) V = IR OR (R = ) V / I (C1) 7(b) (lamp is) brighter OR (brightness) increases B1 resistance of wire and resistor in parallel is less than resistance of wire owtte OR voltage across lamp / L increases B1 (so) current in lamp increases B1

This question in 0625/32 May/June 2024

8 Fig. 8.1 shows part of a circuit for measuring the resistance of a lamp. A Fig. 8.1 (a) Draw on Fig. 8.1 to show how to connect a voltmeter to measure the potential difference across the lamp. Use the electrical symbol for a voltmeter. [2] (b) The current in the lamp is 0.41 A and the potential difference across the lamp is 12 V. Calculate the resistance of the lamp. resistance = … Ω [3] (c) Calculate the electrical power transferred in the lamp. Include the unit. power transferred = … unit … [4] [Total: 9]

9 marks

Mark scheme: 8(a) correct symbol B1 voltmeter in parallel with lamp B1 8(b) 29 () A3 12  0.41 (C2) (R =) V  I OR V = I  R in any form (C1) 8(c) 4.9 A3 0.41  12 OR 0.412  29 (C2) (P =) I  V in any form OR (P =) I 2  R (C1) W B1

This question in 0625/33 May/June 2024

9 A student tests various materials to determine whether they are electrical conductors or insulators. The student uses the circuit shown in Fig. 9.1. 6 V battery switch A X Y Fig. 9.1 (a) The student connects a piece of tin metal between X and Y. Describe how the student can determine whether tin is an electrical conductor. … … … [2] (b) Describe electrical conduction in a metal. Use your ideas about electrons in your answer. … … … … [3] [Total: 5]

5 marks

Mark scheme: 9(a) either: B2 close switch (see if) lamp lights OR reading on ammeter OR lamp lights OR reading on ammeter (so material is (a)) conductor OR lamp lights OR reading on ammeter (so must have electric) current in tin 9(b) mention of free OR de-localised electrons (in the metal) B1 able to move from one atom / ion / particle to another B1 when p.d. OR voltage (applied across the metal / material) B1

This question in 0625/31 Oct/Nov 2024

8 (a) A student connects a circuit with two lamps and three switches, S1, S2 and S3, as shown in Fig. 8.1. 6.0 V S1 S3 S2 Fig. 8.1 (i) The student switches on one lamp. State which switches the student closes to switch on only one lamp. … [1] (ii) The student opens all the switches then switches on two lamps. State which switches the student closes to switch on two lamps. … [1] (b) Fig. 8.2 shows the manufacturer’s information for one of the lamps. voltage = 6.0 V current = 0.53 A Fig. 8.2 Calculate the resistance of the lamp when it is connected to a 6.0 V power source. resistance = … Ω [3] (c) Calculate the electrical power transferred in the lamp when it is connected to a 6.0 V power source. Include the unit. power transferred = … unit … [4] [Total: 9]

9 marks

Mark scheme: 8(a)(i) Switch S1 AND Switch S2 B1 8(a)(ii) Switch S1 AND Switch S3 B1 8(b) 11() A3 6(.0)  0.53 (C2) V = I  R OR (R =) V  I (C1) 8(c) 3.2 A3 0.53 x 6(.0) (C2) (P =) I  V (C1) W B1

This question in 0625/33 Oct/Nov 2024

9 A student set up the electrical circuit that is shown in Fig. 9.1. switch ammeter metal wire battery lamp voltmeter variable resistor Fig. 9.1 (a) Fig. 9.2 shows part of the circuit diagram for the circuit in Fig. 9.1. A battery switch ammeter Fig. 9.2 Complete the circuit diagram in Fig. 9.2 to represent the circuit in Fig. 9.1. Use standard circuit symbols. [4] (b) The potential difference (p.d.) across the lamp is 11 V and the current in the lamp is 0.44 A. Calculate the resistance of the lamp. resistance = … Ω [3] (c) The student moves the sliding contact from position A to position B, as shown in Fig. 9.3. metal bar sliding contact in position A connection to lamp connection to battery coil of resistance wire metal bar sliding contact in position B connection to lamp connection to battery coil of resistance wire Fig. 9.3 State and explain any effect on the current in the circuit when the sliding contact is moved from position A to position B. … … … … [2] [Total: 9]

9 marks

Mark scheme: 9(a) correct symbol for: B1 voltmeter lamp B1 variable resistor B1 lamp and variable resistor connected in series circuit AND B1 voltmeter in parallel with lamp 9(b) 25 () A3 11 ÷ 0.44 (C2) (R =) V ÷ I or V = I  R or in any form (C1) 9(c) current increases B1 (because) resistance (of variable resistor) decreases OR there is less resistance wire (in the circuit / for current to move B1 through)

This question in 0625/32 Feb/March 2025

8 Fig. 8.1 shows the circuit diagram for a 16 Ω resistor and an 8.0 Ω resistor connected to a 6.0 V battery. 6.0 V 16 Ω 8.0 Ω Fig. 8.1 (a) Calculate the combined resistance of the two resistors shown in Fig. 8.1. combined resistance = … Ω [2] (b) The potential difference across the 8.0 Ω resistor is 2.0 V. Calculate the current in the resistor. current = … A [3] (c) State the name of the particles that move through the metal wires when there is a current in the circuit. … [1] (d) A student measures the potential difference across the 16 Ω resistor by using a meter. On Fig. 8.1, draw the electrical symbol for this meter and its connections. [2] [Total: 8]

8 marks

Mark scheme: 8(a) 24 () A2 (combined resistance =) R1 + R2 OR 16 + 8(.0) C1 8(b) (I =) 0.25 (A) A3 (I =) 2(.0) ÷ 8(.0) C2 V = IR in any form OR (I =) V ÷ R C1 8(c) electrons B1 8(d) voltmeter correctly connected across 16  resistor A2 correct voltmeter symbol in wrong place OR incorrect meter connected across 16  resistor C1

This question in 0625/31 May/June 2025

8 Fig. 8.1 shows a mains-powered electric fan heater fixed on a bathroom wall. electric fan heater pull cord Fig. 8.1 The pull cord switches the fan heater on and off. (a) Suggest why a pull cord is safer than a push switch for a fan heater in a bathroom. … … [1] (b) Fig. 8.2 shows the electric circuit for the fan heater. switch mains supply X heater M Y Fig. 8.2 State the name for component X and for component Y. X … Y … [2] (c) Fig. 8.3 shows the information label on the fan heater. power = 2000 W voltage = 230 V Fig. 8.3 Calculate the current supplied to the fan heater. current = … A [3] [Total: 6]

6 marks

Mark scheme: 8(a) reduces risk of electric shock / electrocution OR reference to damp conditions B1 8(b) symbol X: fuse B1 symbol Y: motor B1 8(c) 8.7 (A) A3 2000 ÷ 230 C2 power = current  voltage OR (current =) power ÷ voltage C1

This question in 0625/32 May/June 2025

9 Fig. 9.1 shows two resistors connected in series. 20 Ω 40 Ω Fig. 9.1 (a) Calculate the combined resistance of the two resistors in series. combined resistance = … Ω [1] (b) The two resistors in Fig. 9.1 are connected to an ammeter and a 12 V battery, as shown in Fig. 9.2. 12 V A 20 Ω 40 Ω Fig. 9.2 The reading on the ammeter is 0.20 A. (i) Calculate the potential difference (p.d.) across the 20 Ω resistor. potential difference = … V [3] (ii) A student uses a voltmeter to measure the potential difference across the 20 Ω resistor. Draw on Fig. 9.2 to show how the student connects the voltmeter. Use the correct circuit symbol for the voltmeter. [2] (c) The student removes the two resistors and then connects them in parallel, as shown in Fig. 9.3. 20 Ω 40 Ω Fig. 9.3 Suggest a value for the combined resistance of the two resistors in parallel. combined resistance = … Ω [1] [Total: 7]

7 marks

Mark scheme: 9(a) 60 () B1 9(b)(i) 4(.0) (V) A3 0.2(0)  20 C2 (V =) I  R C1 9(b)(ii) correct circuit symbol for voltmeter B1 candidate’s meter connected in parallel with the 20  resistor B1 9(c) 0  value  20 () e.g. 11 OR 19.5 OR 0.075 OR 13.3 etc. B1

This question in 0625/32 May/June 2025

8 Fig. 8.1 shows a mains-powered electric fan heater fixed on a bathroom wall. electric fan heater pull cord Fig. 8.1 The pull cord switches the fan heater on and off. (a) Suggest why a pull cord is safer than a push switch for a fan heater in a bathroom. … … [1] (b) Fig. 8.2 shows the electric circuit for the fan heater. switch mains supply X heater M Y Fig. 8.2 State the name for component X and for component Y. X … Y … [2] (c) Fig. 8.3 shows the information label on the fan heater. power = 2000 W voltage = 230 V Fig. 8.3 Calculate the current supplied to the fan heater. current = … A [3] [Total: 6]

6 marks

Mark scheme: 8(a) reduces risk of electric shock / electrocution OR reference to damp conditions B1 8(b) symbol X: fuse B1 symbol Y: motor B1 8(c) 8.7 (A) A3 2000 ÷ 230 C2 power = current  voltage OR (current =) power ÷ voltage C1

This question in 0625/33 May/June 2025

9 Fig. 9.1 shows two resistors connected in series. 20 Ω 40 Ω Fig. 9.1 (a) Calculate the combined resistance of the two resistors in series. combined resistance = … Ω [1] (b) The two resistors in Fig. 9.1 are connected to an ammeter and a 12 V battery, as shown in Fig. 9.2. 12 V A 20 Ω 40 Ω Fig. 9.2 The reading on the ammeter is 0.20 A. (i) Calculate the potential difference (p.d.) across the 20 Ω resistor. potential difference = … V [3] (ii) A student uses a voltmeter to measure the potential difference across the 20 Ω resistor. Draw on Fig. 9.2 to show how the student connects the voltmeter. Use the correct circuit symbol for the voltmeter. [2] (c) The student removes the two resistors and then connects them in parallel, as shown in Fig. 9.3. 20 Ω 40 Ω Fig. 9.3 Suggest a value for the combined resistance of the two resistors in parallel. combined resistance = … Ω [1] [Total: 7]

7 marks

Mark scheme: 9(a) 60 () B1 9(b)(i) 4(.0) (V) A3 0.2(0)  20 C2 (V =) I  R C1 9(b)(ii) correct circuit symbol for voltmeter B1 candidate’s meter connected in parallel with the 20  resistor B1 9(c) 0  value  20 () e.g. 11 OR 19.5 OR 0.075 OR 13.3 etc. B1

This question in 0625/33 May/June 2025

9 A teacher connects the circuit shown in Fig. 9.1. ammeter 1 switch lamp 2 lamp 1 V 1.5 cell ammeter 2 Fig. 9.1 (a) Give the name for the way the components are connected in this circuit. … [1] (b) The resistance of each lamp is 8.0 Ω. Calculate the combined resistance of lamp 1 and lamp 2. combined resistance = … Ω [2] (c) The teacher draws a circuit diagram for the circuit in Fig. 9.1. The circuit diagram is not completed. Fig. 9.2 shows the teacher’s incomplete circuit diagram. A ammeter 1 lamp 1 Fig. 9.2 Complete the circuit diagram by adding the symbols correctly connected. [3] [Total: 6]

6 marks

Mark scheme: 9(b) 16 () A2 (combined resistance =) R1 + R2 OR 8(.0) + 8(.0) (C1) 9(c) symbol for switch seen B1 symbol for cell seen B1 symbols connected to give series circuit B1

This question in 0625/31 Oct/Nov 2025

7 Fig. 7.1 shows a lamp connected in series with four 1.5 V cells and an ammeter. A voltmeter is connected across the lamp. A V Fig. 7.1 (a) Determine the potential difference across the four cells. potential difference = … V [1] (b) (i) The reading on the ammeter is 0.64 A. The reading on the voltmeter is 5.8 V. Calculate the resistance of the lamp. resistance of the lamp = … Ω [3] (ii) Calculate the energy transferred by the lamp in 140 s. energy transferred = … J [3] (c) On Fig. 7.1, draw a second lamp so that there is a bigger current in the ammeter when the second lamp is connected. [1] [Total: 8]

8 marks

Mark scheme: 7(a) 6(.0) (V) B1 7(b)(i) 9.1 () A3 5.8 ÷ 0.64 C2 (resistance =) potential difference ÷ current C1 7(b)(ii) 520 (J) A3 5.8  0.64  140 or 3.712  140 or 5.8  89.6 or 0.64  812 C2 (energy transferred =) potential difference  current  time C1 7(c) lamp in parallel with original lamp B1

This question in 0625/32 Oct/Nov 2025

7 (a) A student is making a torch. (i) The torch needs a potential difference (p.d) of 6.0 V. The electromotive force (e.m.f.) of each cell for the torch is 1.5 V. State the number of cells that the torch needs. number of cells = … [1] (ii) The student has the following components for the electrical part of the torch: a 6.0 V lamp a switch several 1.5 V cells connecting wire Draw a circuit diagram to show how the components are connected in series to make the torch. Use standard circuit symbols. [3] (b) The p.d. across the lamp is 6.0 V. The current in the lamp is 0.25 A (i) Calculate the resistance of the lamp. resistance = … Ω [3] (ii) Calculate the power of the lamp. power = … W [3] [Total: 10]

10 marks

Mark scheme: 7(a)(i) 4 (cells) B1 7(a)(ii) three (cell (s) / battery, lamp and switch) circuit symbols correct A2 one or two (from cell(s) / battery, lamp and switch) circuit symbols correct C1 a complete circuit with cell (s), lamp and switch in series B1 7(b)(i) 24 () A3 6(.0) ÷ 0.25 C2 (resistance =) potential difference ÷ current C1 7(b)(ii) 1.5 (W) A3 6(.0)  0.25 C2 (power =) potential difference  current C1

This question in 0625/33 Oct/Nov 2025

8 (a) A coal-fired power station is far from a city. The electricity generated by the power station is transmitted to the city at a high voltage. State two advantages of high-voltage transmission of electricity. 1 … 2 … [2] (b) In the city, transformers reduce the high voltage. Fig. 8.1 shows one of these transformers. transformer black cooling fins ground Fig. 8.1 Transformers become hot when they reduce the high voltage. There are black cooling fins on the casing which contains the transformer. Explain why the fins are black. … … [2] (c) Describe the construction and materials of a simple step-down transformer. You may draw a labelled diagram as part of your answer. … … … [3] [Total: 7]

7 marks

Mark scheme: 8(a) any two from: B2 • smaller current (in cables) • more efficient • less power / heating losses • thinner / cheaper cables / pylons further apart owtte • less voltage drop • allows for transmission over a longer distance • fewer / larger power stations can supply more area / whole country 8(b) (black is a) good / best emitter M1 of thermal radiation / infrared A1 8(c) any three from: B3 • two coils • copper wire / coils • (coils wrapped round / linked by soft) iron core • more turns on primary coil

This question in 0625/33 Oct/Nov 2025