Electrical circuits — Paper 4 · IGCSE Sciences - Co-ordinated (Double) 0654

7 (a) A school orchestra is practising. Table 7.1 shows the highest and lowest sound frequencies of some of the musical instruments in the orchestra. Table 7.1 instrument highest frequency / Hz lowest frequency / Hz cymbals 900 300 flute 2600 260 guitar 1400 80 piano 4200 30 violin 3500 200 (i) State which instrument can produce the sound with the highest pitch. Explain your answer. instrument … explanation … … [2] (ii) State which instrument can produce the sound with the longest wavelength. Explain your answer. instrument … explanation … … [2] (b) A student is playing an electric guitar. The guitar is connected to an amplifier and two loudspeakers as shown in Fig. 7.1. loudspeakers amplifier Fig. 7.1 (i) Each loudspeaker has a resistance of 15 Ω. Calculate the combined resistance of the two loudspeakers when connected in parallel, as shown in Fig. 7.1. Show your working. resistance = … Ω [2] (ii) The amplifier is fitted with a heat sink. This allows unwanted thermal energy to be transferred away from the amplifier. A heat sink is shown in Fig. 7.2. black metal fins heat sink Fig. 7.2 State and explain two features of the heat sink that allow thermal energy to be transferred away from the amplifier. feature 1 … explanation … … feature 2 … explanation … … [2]

8 marks

Mark scheme: 7(a)(i) piano ; highest frequency ; 2 7(a)(ii) piano ; lowest frequency ; 2 7(b)(i) 1 / RT = 1 / R1 + 1 / R2 or working ; 7.5 (Ω) ; 2 7(b)(ii) large surface area – heat can be lost quicker from the surface / for better, conduction / convection / radiation ; black (fins) – black is a good emitter (of radiation) ; metal (fins) – metal is a good conductor (of heat) ; max 2

This question in 0654/42 May/June 2017

3 (a) Five different types of power station are listed. A hydroelectric B gas-fired C nuclear D oil-fired E tidal (i) State the letters of the three types of power station that use a boiler to turn water into steam. … [1] (ii) State the letters of the two types of power station that use renewable energy sources. … [1] (b) Overhead power transmission cables supply electrical energy to a town. Energy losses in the transmission cables can be reduced if the voltage for transmission is increased. (i) Name the device that steps up the voltage of the electricity before transmission. … [1] (ii) It is suggested that less energy is lost during transmission if the resistance of the cable is changed. The resistance of the cable is initially 8.0 Ω. It is suggested that the diameter of the cable should be doubled. Use the relationship • resistance is inversely proportional to (diameter)2 to calculate the resistance of a similar cable that has twice the diameter. resistance = … Ω [2] (c) (i) In a nuclear power station, nuclear fission of uranium-235 atoms takes place. Describe what happens to the atoms of uranium-235 during nuclear fission. … … [1] (ii) Another isotope of uranium, uranium-234, decays by alpha (α) emission to produce an isotope of thorium. Use the correct nuclide notation to complete the symbol equation for this decay process. … … 234 [3] 92U … Th + … He

9 marks

Mark scheme: 2 3(a)(i) B, C and D ; 1 3(a)(ii) A and E ; 1 3(b)(i) transformer ; 1 3(b)(ii) 4 seen in calculation ; 2 (Ω) ; 2 3(c)(i) nuclei are split ; 1 3(c)(ii) 230Th ; 90Th ; 4He ; 3

This question in 0654/41 Oct/Nov 2017

6 (a) A house has an electric doorbell. (i) Draw a circuit diagram to show a doorbell connected in series with a switch and a battery. Use the circuit symbol, , for an electric bell. [2] (ii) The bell produces a sound when a metal hammer strikes it. Describe how this action produces a sound. … … [1] (b) The house has a heater filled with water at 20 °C. Fig. 6.1 shows the heater. 0.012 m3 of water at 20 °C steel casing heating element Fig. 6.1 The heating element supplies 2 000 000 J of energy to the 0.012 m3 of water. The density of water at 20 °C is 1000 kg / m3. The specific heat capacity of water is 4200 J / (kg °C). (i) Show that the maximum temperature that the water will reach is approximately 60 °C. State any formula you use and show your working. formula working [4] (ii) Suggest why the water will not reach the temperature you calculated in (b)(i). … … [1]

8 marks

Mark scheme: 6(a)(i) all symbols correct ; all connected correctly in series circuit and all else correct ; 2 6(a)(ii) vibration / oscillation ; 1 6(b)(i) m=dV OR 1000 × 0.012 OR 12 (kg) ; ( ) 2000000 OR 12 4200 E T mc ∆ = × 40 oC ; maximum temperature = 40 + 20 oC (= 60 oC) ; 4 6(b)(ii) thermal energy is lost (to surroundings / casing ) ; 1

This question in 0654/41 Oct/Nov 2017

9 (a) A boy riding his bicycle is cooled by sweating. Describe, in terms of molecules, how sweating cools his body by evaporation. … … … … … [3] (b) Fig. 9.1 shows a car behind a bicycle at night. Fig. 9.1 A reflector on the back of the bicycle is made from many small red plastic prisms, one of which is shown in Fig. 9.2. A ray of light from the headlamp of the car enters the prism. ray of light from the headlamp of the following car red plastic prism Fig. 9.2 Total internal reflection occurs within the prism. On Fig. 9.2, complete the path taken by the ray of light until it emerges from the prism. [2] (c) The bicycle has a lamp powered by a small generator. The generator turns as the boy pedals and the lamp lights up. Fig. 9.3 shows a simple version of the generator. axle magnet magnet N S slip ring coil brush lamp Fig. 9.3 Describe how the rotating coil causes the lamp to light. … … … … … … [3] (d) The generator produces an alternating voltage. Fig. 9.4 shows how the output voltage of the bicycle generator changes with time. 6.0 4.0 2.0 voltage / V 0 time / s 0.02 0.04 0.06 0.08 0.10 –2.0 –4.0 –6.0 Fig. 9.4 (i) Calculate the frequency of the alternating voltage. Show your working. frequency = … Hz [1] (ii) State the amplitude of the alternating voltage. amplitude = … V [1] (e) A different bicycle has a front lamp, A, and a rear lamp, B, powered by the same battery. Fig. 9.5 shows how the lamps are connected. 12 V A B Fig. 9.5 (i) State the name given to this arrangement of lamps in a circuit. … [1] (ii) Lamp A has a resistance of 5 Ω. The battery has a voltage of 12 V. Calculate the current flowing through lamp A when the switch is closed. State the formula you use and show your working. formula working current = … A [2] (iii) Lamp B has a resistance of 10 Ω. Calculate the combined resistance of the two lamps in this circuit. Show your working. resistance = … Ω [2]

15 marks

Mark scheme: 9(a) fastest moving / most energetic molecules escape ; remainder are slower / have less energy ; energy used taken from surroundings / molecules gain energy from body ; 3 9(b) first 90° reflection correct ; second 90° reflection correct ; 2 9(c) rotation of coil, cuts magnetic field / experiences changing magnetic field ; induces an emf ; current flows through lamp / pd across lamp causes lamp to light ; 3 9(d)(i) frequency = 25 (Hz) ; 1 Question Answer Marks 9(d)(ii) amplitude = 5 (V) ; 1 9(e)(i) parallel ; 1 9(e)(ii) I = V / R or 12 / 5 ; 2.4 (A) ; 2 9(e)(iii) 1 2 1 2 T R R R R R = + or R = 10 / 3 (Ω) ; = 3.3 (Ω) ; 2

This question in 0654/42 Oct/Nov 2017

3 (a) A torch (flashlight) contains four cells connected in series and two lamps X and Y connected in parallel. Each lamp has a separate switch. (i) Draw a circuit diagram for the torch using electrical circuit symbols. [3] (ii) The current passing through lamp X is 0.5 A. The resistance of lamp X is 12 Ω. Calculate the total potential difference supplied by the four cells. State the formula you use and show your working. formula working potential difference = … V [2] (iii) Calculate the charge passing through lamp X in two minutes. State the formula you use and show your working. formula working charge = … C [2] (b) Fig. 3.1 shows a torch shining at a plane mirror. Fig. 3.1 A ray of light reflects off the mirror. (i) Complete Fig. 3.1 to show the ray of light reflecting off the mirror. [2] (ii) On Fig. 3.1, mark and label the angle of incidence with the letter i. [1] (iii) The angle of incidence is 45°. State the angle of reflection. Explain your answer. angle of reflection … ° explanation … … [1]

11 marks

Mark scheme: 3(a)(i) two lamps in parallel ; each switch operates one lamp only ; all symbols and everything else correct ; 3 3(a)(ii) voltage = current × resistance or 0.5 × 12 ; = 6 (V) ; 2 3(a)(iii) charge = current × time or 0.5 × 120 ; = 60 (C) ; 2 3(b)(i) ray reflects ; at approximately correct angle ; 2 3(b)(ii) angle i correctly labelled ; 1 3(b)(iii) 45° AND angle of incidence = angle of reflection ; 1

This question in 0654/41 Oct/Nov 2018

12 (a) Fig. 12.1 shows a bicycle with a front lamp A and a rear lamp B powered by the same battery. A B Fig. 12.1 Fig. 12.2 is a circuit diagram to show how the lamps are connected. 9.0 V A B Fig. 12.2 (i) Lamp A has a resistance of 16.0 Ω and lamp B has a resistance of 8.0 Ω. Calculate the combined resistance of the two lamps in this circuit when both switches are closed. Show your working. resistance = … Ω [2] (ii) Calculate the power of lamp B. State any formula you use, show your working and give the unit of your answer. formula working power = … unit … [4] (b) One of the lamps is shown in Fig. 12.3. glass bulb, filled with gas wire filament metal base Fig. 12.3 The hot lamp transfers thermal energy. (i) Name the process that transfers thermal energy through the metal base. … [1] (ii) Name the two processes that transfer thermal energy between the hot wire filament and the glass bulb. 1 … 2 … [1] (c) The cyclist has a flat tyre. She pumps up the flat tyre with a volume of 3168 cm3 of air at atmospheric pressure. When the tyre is inflated, the volume of air in the tyre is 1441 cm3. Assume that there was no air in the flat tyre. The pressure of the air in the inflated tyre is 2.22 × 105 N / m2. The temperature of the air does not change. (i) Write down the value of the inflated tyre pressure in pascals (Pa). … Pa [1] (ii) Calculate the atmospheric pressure in N / m2. State the formula you use and show your working. formula working atmospheric pressure = … N / m2 [2]

11 marks

Mark scheme: 12(a)(i) 5.3(3) (Ω) ; 2 12(a)(ii) current = voltage / resistance or 9 / 8 OR 1.1(25) (A) ; power = voltage × current or 9 × 1.125 ; = 10(.125) ; Watts / W ; 4 12(b)(i) conduction ; 1 12(b)(ii) convection AND radiation ; 1 12(c)(i) 2.22 × 105 (Pa) ; 1 12(c)(ii) P1 = (P2 × V2) / V1 or (2.22 × 105× 1441) / 3168 ; = 1.01 × 105 (N / m2) ; 2

This question in 0654/42 Oct/Nov 2018

12 (a) The body of a car is usually made from steel. The bodies of some cars are made from aluminium. Suggest a simple way of deciding whether the body of a car is made from either steel or aluminium. Explain your answer. … … … [1] (b) In a car, relays are often used as switches in electrical circuits that use large currents. Explain why relays are used in this way. … … … [1] (c) A car driver uses mirrors to see behind the car. Fig. 12.1 shows a ray of light striking a mirror. mirror Fig. 12.1 (i) On Fig. 12.1, draw the normal at the point where the ray strikes the mirror and label with the word normal. [1] (ii) On Fig. 12.1, draw the reflected ray and label with the words reflected ray. [1] (iii) On Fig. 12.1, mark the angle of reflection and label with the letter r. [1] (d) Fig. 12.2 shows a black car and a white car. Fig. 12.2 The cars are parked next to each other on a sunny day. Suggest why the black car gets hotter than the white car. … … [1] (e) The black car accelerates up a hill. Apart from thermal energy, state two forms of energy gained by the car as it accelerates up the hill. 1 … energy 2 … energy [2] (f) During a journey, the black car travels 1500 m along a straight road in 90 s. The driving force of the car’s engine is 14 000 N. (i) Calculate the work done by the driving force. State the formula you use and show your working. formula working work done = … J [2] (ii) Calculate the useful power output from the car’s engine during this period. State the formula you use, show your working and state the unit of your answer. formula working power = … unit … [3]

13 marks

Mark scheme: 12(a) use a magnet (no mark) steel is magnetic / attracted to a magnet ; 1 12(b) to switch high current circuits using a small current circuit / so a high current circuit can be switched safely / so that a switch with a low current rating can be used to switch a high current ; 1 12(c)(i) normal drawn and labelled ; 1 12(c)(ii) reflected ray drawn with approx. correct angle of reflection ; 1 12(c)(iii) correctly labelled angle of reflection ; 1 12(d) black surfaces are better absorbers of thermal radiation (than white surfaces) / white surfaces are better reflectors of thermal radiation (than black surfaces) ; 1 12(e) kinetic ; gravitational (potential) ; 2 12(f)(i) work = force × distance or 14 000 × 1500 ; = 21 000 000 (J) ; 2 12(f)(ii) power = energy time or work time or 21000000 90 ; = 230 000 ; W ; 3

This question in 0654/43 Oct/Nov 2018

6 (a) Fig. 6.1 shows a car with two rear lamps, L1 and L2. L1 L2 Fig. 6.1 The lamps are connected in parallel and powered by a 12 V battery. The lamps each have a resistance of 33 Ω. (i) Calculate the combined resistance of the two lamps connected in parallel in this circuit. Show your working. resistance = … Ω [2] (ii) Calculate the charge that passes through lamp L2 in 30 minutes. State any formula you use and show your working. charge = … C [4] (b) The air in a car tyre exerts a pressure on the walls of the tyre. (i) Use ideas about the motion of molecules to describe how the molecules exert a pressure on the walls of the tyre. … … … [2] (ii) State what happens to the pressure of the air in the tyre if the temperature increases. … … [1] (c) Hot exhaust gases from the car engine leave the engine through a steel exhaust pipe. The steel exhaust pipe transfers thermal energy through the pipe wall by conduction. (i) Describe the process of conduction in a solid, using ideas about particle vibration and transfer by electrons. … … … … … … [3] (ii) When heated, the steel exhaust pipe expands. Explain, in terms of the motion and arrangement of particles, why a solid expands less than a gas when heated. … … … … … [2] [Total: 14]

14 marks

Mark scheme: 6(a)(i) RT = 16.5 (Ω) ; 2 6(a)(ii) current = voltage / resistance or 12 / 33 ; = 0.36 (A) ; charge = current × time or 0.36 × 30 (× 60) ; = 650 (C) ; 4 6(b)(i) (molecules) collide with / hit / rebound from, walls of tyre ; exerting a force ; 2 6(b)(ii) increases ; 1 6(c)(i) incident energy makes particles, vibrate more / gain energy ; this, vibration / energy, is transferred from particle to particle ; reference to, delocalised / free, electrons ; (delocalised / free) electrons transfer energy through the solid ; max 3 6(c)(ii) stronger forces of attraction between particles in solid ; particles in solid are in fixed positions or particles in gas are free to move throughout the gas ; 2

This question in 0654/42 May/June 2019

3 (a) Fig. 3.1 shows a potato being baked in the oven of an electric cooker. potato metal skewer heating element Fig. 3.1 The potato has a metal skewer (a long metal pin) pushed through it. (i) The air in the oven is heated by the heating element. On Fig. 3.1 draw an arrow to show how the heated air moves inside the oven. [1] (ii) Name the main method of thermal energy transfer in the heated air. … [1] (iii) The metal skewer transfers heat to the inside of the potato by conduction. Describe the process of conduction in a solid, using ideas about particle vibration. … … … … [2] (b) The cooker has four electric hotplates, A, B, C and D. These are each connected in parallel with each other across the mains voltage supply. Each hotplate is operated by a separate switch. Each hotplate has a resistance of 60 Ω. Fig. 3.2 shows the circuit. The hotplates are represented by resistor symbols. A B C D Fig. 3.2 (i) Show that the combined resistance of hotplates A and B connected in parallel is 30 Ω. [2] (ii) State the combined resistance of hotplates C and D connected in parallel. … Ω [1] (c) A saucepan containing water is placed on a hotplate. When the temperature of the water reaches the boiling point of water, the water boils. (i) State the boiling point of water. … °C [1] (ii) When the water boils, the liquid water turns into steam. Describe the differences between liquid water and steam in terms of: • the forces and distances between the molecules • the motion of the molecules. … … … … … [3] [Total: 11]

11 marks

Mark scheme: 3(a)(i) arrow showing heated air rising ; 1 3(a)(ii) convection ; 1 3(a)(iii) particles vibrate more / gain energy ; this vibration is passed through metal ; 2 3(b)(i) use of correct formula ; evidence of correct working ; 2 3(b)(ii) 30 Ω ; 1 3(c)(i) 100 (°C) ; 1 3(c)(ii) stronger forces of attraction between water molecules in liquid ; water molecules are closer together in liquid ; water molecules have greater freedom of movement / collide less frequently in steam / owtte ; 3

This question in 0654/41 Oct/Nov 2019

6 (a) Describe how thermal energy passes through copper by conduction. … … … … [2] (b) Copper boils at 2562 °C. Describe two differences between boiling and evaporation. 1 … … 2 … … [2] (c) Equal volumes of air, copper and water are heated from 10 °C to 90 °C. State which of these materials will expand: most … least. … [1] (d) A copper wire of length 0.5 m has a resistance of 0.02 Ω. Determine the resistance of another copper wire of length 0.25 m that has twice the cross- sectional area. resistance = … Ω [2] (e) Two wires are connected in parallel. One wire has a resistance of 0.40 Ω. The other wire has a resistance of 0.60 Ω. Calculate the combined resistance of the two wires connected together in parallel. resistance = … Ω [2] (f) Copper wire is used in the coil of a generator. Fig. 6.1 shows a simple a.c. generator. Fig. 6.1 (i) On Fig. 6.1 label the coil with the letter C. [1] (ii) An electromotive force (e.m.f.) is induced in the rotating coil. State two factors that would increase the magnitude of the induced e.m.f. 1 … 2 … [2] [Total: 12]

12 marks

Mark scheme: 6(a) thermal energy transferred as (vibrational) energy of atoms ; vibrations passed from atom to atom ; delocalised electrons transfer energy ; max 2 Question Answer Marks 6(b) evaporation can occur at any temperature / boiling occurs at the boiling point; evaporation happens only at the surface / boiling occurs throughout the liquid; during boiling all / most moleculaes have enough energy to leave / evaporation only lets the molecules with the greatest kinetic energy escape; evaporation can occur using the internal energy of the system / boiling requires a(n external) source of heat; evaporation is a slow process / boiling is a rapid process; evaporation produces cooling / boiling does not produce cooling; max 2 6(c) most – air and least copper ; 1 6(d) evidence of division by 2 twice; 0.005 (Ω) ; 2 6(e) 1/RT = 1/R1 + 1/R2 or RT = R1 R2 /R1 + R2 or correct substitution; 0.24 (Ω) ; 2 6(f)(i) coil labelled correctly; 1 6(f)(ii) rotate coil faster ; increase magnetic field strength ; 2

This question in 0654/41 May/June 2020

3 (a) A car has two identical headlamps L1 and L2. The lamps are connected in parallel across a 12 V battery as shown in Fig. 3.1. L1 L2 Fig. 3.1 (i) The current passing through L1 is 5.0 A. Show that the resistance of L1 is 2.4 Ω. [2] (ii) Calculate the combined resistance of the two lamps connected in parallel. resistance = … Ω [2] (iii) State one reason why the lamps are connected in parallel rather than in series. … … … [1] (b) The headlamps emit visible light. The frequency of some of this light is 6.0 × 1014 Hz. Calculate the wavelength of this light. wavelength = … m [3] (c) The car engine is noisy and emits sound waves that pass through the air as a series of compressions and rarefactions. Fig. 3.2 shows the positions of the compressions and rarefactions as the sound wave passes through the air. Fig. 3.2 (i) On Fig. 3.2 label the centre of a rarefaction with the letter R. [1] (ii) Explain in terms of compressions what is meant by the frequency of a sound wave. … … [1] (d) The steel radiator on the car transfers thermal energy through the radiator wall by conduction. Describe how thermal energy passes through a metal by conduction. … … … … … [2] [Total: 12]

12 marks

Mark scheme: 3(a)(i) R = V ÷ I; = 12 ÷ 5.0; (= 2.4 Ω) 3(a)(ii) 1/RT = 1/R1 + 1/R2 or RT = R1 R2 /R1 + R2 or correct substitution; 1.2 (Ω); 2 3(a)(iii) both lamps get full voltage; if one lamp fails the other will still work; 1 3(b) v = f × λ or correct substitution; (speed of light =) 3 × 108 (m) seen; = 5 × 10–7 (m); 3 3(c)(i) rarefaction correctly labelled with the letter R; 1 3(c)(ii) number of compressions per second; 1 3(d) thermal energy transferred as (vibrational) energy of atoms ; vibrations passed from atom to atom ; delocalised electrons transfer energy ; max 2

This question in 0654/42 May/June 2020

3 (a) A car travels along a road at 8 m / s. Describe the difference between the terms speed and velocity. … … … [1] (b) Some puddles of water have formed on the road. Explain, in terms of water molecules, how the rate of evaporation of water from a puddle is affected by the strength of the wind blowing across the puddle. … … … … [2] (c) The car battery has an electromotive force (e.m.f.) of 12 V. State what is meant by electromotive force. … … … [2] (d) Fig. 3.1 shows part of the lighting circuit for the car. Two lamps, L1 and L2, each have a resistance of 16 Ω. 12 V fuse L1 L2 Fig. 3.1 (i) When the switch is closed the current in the fuse is 1.5 A. Determine the current in L1. current = … A [1] (ii) State one reason why the lamps are connected as shown in Fig. 3.1 and not in series. Explain your answer. … … … [2] (e) Modern cars use optical fibres to transfer information using visible light rays. Fig. 3.2 shows a ray of light entering an optical fibre. ray of light optical fibre Fig. 3.2 (i) Explain why the ray of light is able to stay inside the optical fibre. You may draw on Fig. 3.2 if it helps your answer. … … … … [2] (ii) Visible light rays are transverse waves. Draw labelled diagrams to show the difference between a transverse wave and a longitudinal wave. [2] [Total: 12]

12 marks

Mark scheme: 3(a) speed has magnitude only / velocity has magnitude and direction / velocity has direction / speed does not have direction ; 1 3(b) increase in wind strength increases rate of evaporation / ORA ; (stronger wind) allows more molecules to escape / evaporate into the air above the puddle / ORA ; 2 3(c) the energy / work done (supplied by a source) ; per (unit) charge ; 2 3(d)(i) 0.75 (A) ; 1 Question Answer Marks 3(d)(ii) if one lamp fails the other will still work ; if one lamp fails still a complete circuit ; OR ref. to full brightness / brighter lamps ; because they each receive the full voltage ; 2 3(e)(i) ref. to total internal reflection / owtte / shown on diagram ; angle of incidence greater than the critical angle ; 2 3(e)(ii) correct diagrams for transverse and longitudinal waves ; vibrations perpendicular to direction of travel for transverse and parallel for longitudinal ; 2

This question in 0654/41 Oct/Nov 2020

9 (a) The information booklet about an oven states that the weight of the oven is 45 kg. Explain why this statement is incorrect. … … [1] (b) (i) Fig. 9.1 shows information on a label attached to the electric oven. 240 V 6000 W Fig. 9.1 Use Fig. 9.1 to calculate the maximum working current of the oven. current = … A [2] (ii) The oven has its own fuse. Use your answer to (b)(i) to explain why a fuse rated at 13 A is not suitable for use in the oven circuit. … … … [1] (c) A thermocouple is used to measure the temperature inside the oven. Describe the structure of a thermocouple. You may draw a diagram if it helps your answer. … … … [2] (d) Some water is heated in a dish in the oven. As the water is heated, some of the water evaporates. Eventually the water begins to boil. Describe two differences between evaporation and boiling. 1 … … 2 … … [2] [Total: 8]

8 marks

Mark scheme: 9(a) mass is measured in kg / weight is measured in newtons; 1 9(b)(i) I = P / V or working 6000 / 240; current = 25 (A); 2 9(b)(ii) fuse rating should be higher than working current / fuse will blow ; 1 9(c) two different metals ; joined together / to make junction(s) ; 2 Question Answer Marks 9(d) evaporation can occur at any temperature / boiling occurs at the boiling point ; evaporation happens only at the surface / boiling occurs throughout the liquid ; during boiling, all / most, molecules have enough energy to leave / evaporation only lets the molecules with the greatest kinetic energy escape ; evaporation can occur using the internal energy of the system / boiling requires a(n external) source of heat ; evaporation is a slow process / boiling is a rapid process ; evaporation produces cooling / boiling does not produce cooling ; max 2 2

This question in 0654/42 Oct/Nov 2020

9 (a) Fig. 9.1 shows a bicycle with a front lamp F and a rear lamp R, powered by a 9 V generator (dynamo). R F Fig. 9.1 Fig. 9.2 shows the circuit diagram for the lamps. F R Fig. 9.2 Lamp F has a resistance of 12 Ω and lamp R has a resistance of 6 Ω. (i) Calculate the combined resistance of the two lamps in this circuit. resistance = … Ω [2] (ii) Lamp R is switched on. Show that the current in lamp R is 1.5 A. [2] (iii) Calculate the charge that passes through lamp R in 300 seconds. State the unit of your answer. charge = … unit … [3] (iv) The generator supplies an alternating current to light the lamps. Describe the difference between alternating current (a.c.) and direct current (d.c.). … … … [1] (v) State the useful energy transformation that occurs in the generator. from … energy to … energy [1] (vi) State the useful energy transformation that occurs in the lamp. from … energy to … energy [1] (b) The generator is noisy and emits sound waves that pass through the air. Sound waves are longitudinal waves and visible light waves are transverse waves. (i) Give one other example of a transverse wave. … [1] (ii) The sound waves pass through the air as a series of compressions (C) and rarefactions (R). Fig. 9.3 shows the positions of the compressions and rarefactions as the sound wave passes through the air. C R C R C R C R C R Fig. 9.3 On Fig. 9.3, mark one wavelength with a double headed arrow ( ). [1] (iii) Describe how the distance between two compressions changes if the frequency of the sound wave increases. … … [1] [Total: 13]

13 marks

Mark scheme: 9(a)(i) use of 1 / R = 1 / R1 + 1 / R2 or 1 2 1 2 R R R + R or substitution ; 4 (Ω) ; 2 9(a)(ii) (current =) voltage / resistance ; 9 / 6 = (1.5 A) ; 2 9(a)(iii) (charge =) current × time / I × t / 1.5 × 300 ; = 450 ; C ; 3 9(a)(iv) in direct current (DC), the electric charge / current only flows in one direction or in alternating current (AC), the electric charge / current changes direction (periodically) ; 1 9(a)(v) kinetic (energy) to electrical (energy) ; 1 9(a)(vi) electrical (energy) to light (energy) ; 1 Question Answer Marks 9(b)(i) any named electromagnetic wave (apart from light) / water waves; 1 9(b)(ii) one wavelength correctly shown; 1 9(a)(iii) (distance between compressions) decreases ; 1

This question in 0654/43 Oct/Nov 2020

9 Visible light is a transverse wave and is part of the electromagnetic spectrum. (a) State what is meant by a transverse wave. … … [1] (b) Fig. 9.1 shows a ray of visible light from a torch (flashlight) shining into a rectangular glass block. glass air Fig. 9.1 (i) Complete Fig. 9.1 to show the path the ray takes through and out of the block. [2] (ii) State the term used to describe what happens to the ray of light as it enters the glass block. … [1] (iii) Explain why this happens to the ray of light. … … [1] (c) Fig. 9.2 shows the electrical circuit used in the torch. Fig. 9.2 When the switch is closed, the current in the lamp is 1.8 A and the potential difference across the lamp is 3.0 V. Calculate the power output of the lamp. power = … W [2] (d) Fig. 9.3 shows two lamps, identical to the torch lamp, connected in parallel. A Fig. 9.3 (i) When the switch is closed, the ammeter reads 2.6 A. State the current in each lamp. current = … A [1] (ii) Calculate the quantity of charge passing through one of the lamps in Fig. 9.3 when it is switched on for 30 seconds. Give the correct unit for your answer. charge = … unit = … [3] [Total: 11]

11 marks

Mark scheme: 9(a) vibrations / oscillations, are perpendicular to direction of energy transfer ; 1 9(b)(i) ray moves towards the normal inside glass block ; ray emerges parallel to incidence ray ; 2 9(b)(ii) refraction ; 1 9(b)(iii) change of speed / caused by change in density of medium ; 1 9(c) (P=) IV / 1.8 × 3.0 ; 5.4 (W) ; 2 9(d)(i) 1.3 (A) ; 1 Question Answer Marks 9(d)(ii) (Q =) It / 1.3 × 30 ; 39 ; C / Coulombs ; 3

This question in 0654/42 Feb/March 2021

3 Fig. 3.1 shows a circuit used by a student to investigate the resistance of a metal wire. A wire V Fig. 3.1 (a) Suggest why a fixed resistor has been included in the circuit. … … [1] (b) When the switch is closed, the voltmeter reads 1.2 V and the ammeter reads 0.40 A. (i) Calculate the resistance of the wire. resistance = … Ω [2] (ii) Calculate the amount of energy dissipated by the wire in 15 seconds. State the unit of your answer. energy = … unit = … [3] (iii) State the energy transfer happening in the wire as current passes through it. from … energy to … energy [1] (c) The wire is replaced with a second wire made of the same metal and of the same length but with twice the cross‑sectional area. Determine the resistance of the second wire. resistance = … Ω [1] (d) The student wants to calculate the cross‑sectional area of the wire. State the quantity the student needs to measure and suggest a suitable measuring instrument to use. quantity … measuring instrument … [2] (e) Fig. 3.2 shows the wire being placed in between the poles of a permanent magnet. This causes a force to act on the wire. N direction of current S Fig. 3.2 (i) Draw an arrow on Fig. 3.2 to show the direction of the force acting on the wire. [1] (ii) State two ways to increase the size of the force acting on the wire. 1 … … 2 … … [2] [Total: 13]

13 marks

Mark scheme: 3(a) to reduce the potential difference across wire / to reduce the current through the wire / to stop wire melting / heating ; 1 3(b)(i) R = V / I or 1.2 / 0.40 ; 3.0 (Ω) ; 2 3(b)(ii) (E=) VIt or 0.40x1.2x15 ; 7.2 ; joules / J ; 3 3(b)(iii) electrical and thermal ; 1 3(c) 1.5 (Ω) ; 1 3(d) measure the diameter ; use a micrometer screw gauge ; 2 3(e)(i) downwards arrow ; 1 3(e)(ii) increase current ; increase strength of the magnetic field ; 2

This question in 0654/41 May/June 2021

3 (a) Fig. 3.1 shows four electrical component names and their symbols. Draw lines to match each component name with its symbol. One line has been drawn as an example. component symbol fixed resistor light dependent resistor thermistor variable resistor Fig. 3.1 [2] (b) A student investigates how the resistance of a thermistor changes with temperature. Fig. 3.2 shows the results of this investigation. 25 20 15 resistance (kΩ) 10 5 0 0 10 20 30 40 50 temperature (°C) Fig. 3.2 (i) Using Fig. 3.2, state the temperature when the resistance of the thermistor is 5 kΩ. temperature = … °C [1] (ii) Calculate the total resistance of two identical thermistors placed in series when the resistance of each thermistor is 5 kΩ. total resistance = … kΩ [1] (iii) Calculate the total resistance of two identical thermistors placed in parallel when the resistance of each thermistor is 5 kΩ. total resistance = … kΩ [2] (c) A fixed resistor has a current of 3.4 A passing through it. Calculate the charge passing through the fixed resistor during 25 seconds. State the unit of your answer. charge = … unit … [3] [Total: 9]

9 marks

Mark scheme: 3(a) ;; 2 3(b)(i) 32 (oC) ; 1 3(b)(ii) (total resistance =) 10 (kΩ) ; 1 3(b)(iii) 1 / R = 1 / R + 1 / R or 1 / R = 1 / 5 +1 / 5 ; 2.5 (kΩ) ; 2 3(c) (Q =) I t or 3.4 × 25 ; 85 ; C ; 3

This question in 0654/42 Oct/Nov 2021

6 Fig. 6.1 shows a baby elephant born in a wildlife sanctuary. The elephant is undergoing a routine health check. 480 kg Fig. 6.1 (a) Explain what is wrong with the statement “the weight of the elephant is 480 kg”. … … [1] (b) The top speed for a fully grown elephant is 11 m / s. Calculate the maximum distance that can be covered by an elephant in 120 seconds. distance = … m [2] (c) The wildlife sanctuary uses enclosures to keep the elephants safe. Fig. 6.2 shows an enclosure surrounded by four lamps. Fig. 6.2 The lamps are connected in parallel. A switch controls the a.c. power supply to the lamps. (i) Complete the circuit diagram to show the lamps connected in parallel. Include the switch in your diagram. The a.c. power supply has been drawn for you. a.c. power supply [2] (ii) The current through the a.c. power supply is 16 A. Draw a circle around the correct current through each lamp. 2 A 4 A 16 A 32 A 64 A [1] (iii) The potential difference across each lamp is 240 V. Calculate the power output of each lamp. power = … W [2] [Total: 8]

8 marks

Mark scheme: 6(a) 480 kg is the mass / weight should be in Newtons ; 1 6(b) (d =) vxt or 11  120 ; 1320 (m) ; 2 6(c)(i) switch controls all lamps ; 4 lamps in parallel and all else correct ; 2 6(c)(ii) 4 A ; 1 6(c)(iii) (P =) IV / 4  240 ; 960 (W) ; 2

This question in 0654/42 May/June 2022

9 A student investigates the effect of changing temperature on the current through a thermistor. The student connects a cell, an NTC thermistor, an ammeter and a switch in series. (a) On Fig. 9.1, complete the circuit diagram to show the circuit used by the student. Fig. 9.1 [2] (b) The graph in Fig. 9.2 shows the results obtained by the student. 30 25 20 current / mA 15 10 5 0 0 20 40 60 80 100 temperature / °C Fig. 9.2 The temperature of the thermistor is 40 °C. Calculate the time it takes for 1.0 C of charge to flow through the thermistor. time = … s [3] (c) The student uses a liquid-in-glass thermometer to measure temperature. Fig. 9.3 shows the structure of a liquid-in-glass thermometer. glass ethanol Fig. 9.3 (i) Thermal energy is transferred through the glass to the ethanol. Describe how thermal energy is transferred through glass. … … … [2] (ii) The ethanol in the thermometer expands as the temperature increases. Explain why the ethanol expands as the temperature increases in terms of the motion and arrangement of molecules. … … … … [2] (iii) The volume of the ethanol in the thermometer at 25 °C is 2.00 cm3 and the density of the ethanol is 0.78 g / cm3. When the thermometer is cooled to 3 °C, the volume decreases to 1.95 cm3. Calculate the density of the ethanol at 3 °C. density of ethanol = … g / cm3 [3] [Total: 12]

12 marks

Mark scheme: 9(a) 2 correct symbols ; correct circuit ; 9(b) (from graph I =) 5 (mA) / 0.005 (A) ; 3 (t =) Q / I or 1 / 0.005 ; (t =) 200 (s) ; 9(c)(i) conduction ; 2 vibrations passed from particle to particle ; 9(c)(ii) kinetic energy / speed of molecules increases ; 2 molecules move further apart ; 9(c)(iii) (m =) ρ  V OR 0.78  2.0 OR 1.56 (g) ; 3 (ρ =) m / V OR 1.56 / 1.95 ; (ρ =) 0.80 (g / cm3) ;

This question in 0654/41 Oct/Nov 2022

6 Fig. 6.1 shows a temporary zebra enclosure in a wildlife conservation park. The enclosure is surrounded by an electric fence. Fig. 6.1 (a) The fence is powered by an e.m.f. of 2000 V and carries a current of 80 mA. (i) Calculate the total resistance of the fence. total resistance = … Ω [3] (ii) The fence is made of two identical cables connected in parallel. The cables act as resistors. Fig. 6.2 shows the circuit used in the electric fence. cables Fig. 6.2 Use your answer to 6(a)(i) to calculate the resistance of one of the cables. resistance = … Ω [2] (iii) A different enclosure uses a fence made of cables that are the same thickness but twice the length of those shown in Fig. 6.1. State the effect of doubling the cable length on the resistance of the fence. … [1] (b) One of the zebras is startled by a loud sound. (i) Describe how sound waves are transmitted in air. … … [1] (ii) After hearing the sound, the zebra runs across the enclosure in 7.5 s. The average speed of the zebra is 16 m / s. Calculate the distance the zebra runs. distance = … m [2] (c) Fig. 6.3 shows one of the zebras in the enclosure. The zebra has black and white stripes. Fig. 6.3 A vet uses an infrared camera to measure the temperature of the zebra. The infrared camera shows that the black stripes are a different temperature to the white parts of the zebra. Describe and explain the difference in temperature recorded. … … … … [2] [Total: 11]

11 marks

Mark scheme: 6(a)(i) (I =) 0.08 A ; 3 (R =) V / I or 2000 / 0.08 ; (R =) 25000 (Ω) ; 6(a)(ii) use of 1 / RT =1 / R + 1 / R ; 2 (R =) 50000 (Ω) ; 6(a)(iii) (resistance) doubles ; 1 6(b)(i) rarefaction and compressions ; 1 6(b)(ii) (d =) v  t or 167.5 ; 2 (d =) 120 (m) ; 6(c) black will show the higher temperature / ORA ; 2 black emits more (infrared) radiation than white ;

This question in 0654/42 Oct/Nov 2022

9 Fig. 9.1 shows the equipment used by a teacher to demonstrate the properties of ionising radiation to a group of students. They are using a source which emits β-particles. radiation detector counter 019 source emitting β-particles Fig. 9.1 (a) The radioactive source can be moved further away from the radiation detector. The teacher measures the distance between the source and the radiation detector and records the count rate using the laptop. Fig. 9.2 shows the results plotted as a graph. 200 150 counts per minute 100 50 0 0 10 20 30 40 50 distance / cm Fig. 9.2 (i) Describe the trend shown in Fig. 9.2. … … … … [2] (ii) Use Fig. 9.2 to explain why the teacher tells the students to stand at least 2 m away from the radioactive source for their own safety. … … … … [2] (iii) The teacher replaces the radioactive source with one which only emits α-particles. The source which only emits α-particles also measures a count rate of 200 per minute at a distance of 0 m. On Fig. 9.2, draw a line to show the results the teacher obtains when using the source which emits only α-particles. [2] (b) Fig. 9.3 shows the information sticker on the laptop. power input = 65 W potential difference = 19.5 V Fig. 9.3 (i) The laptop has an efficiency of 80%. Calculate the useful power output of the laptop. power = … W [2] (ii) Power for the laptop comes from a 230 V supply through a device in the charger which changes the potential difference to 19.5 V. State the name of this device. … [1] [Total: 9]

9 marks

Mark scheme: 9(a)(i) as distance increases, count rate decreases ; 2 largest decrease at shortest distances / owtte ; 9(a)(ii) beta particles, are ionising/can cause cancer/damages cells/damages DNA or genetic material ; 2 beta particles travel less than 2 m in air / count rate at 2 m is (almost) zero / very few (beta particles) after 50 cm ; 9(a)(iii) correct shape starting at 200 counts per min ; 2 (curve) drawn lower than beta ; 9(b)(i) (power output =) 65  0.8 ; 2 52 (W) ; 9(b)(ii) (step-down) transformer ; 1

This question in 0654/43 Oct/Nov 2022

12 Fig. 12.1 shows a circuit containing two resistors connected in parallel with a 9.0 V battery. 9.0 V 12.0 Ω 6.0 Ω Fig. 12.1 (a) (i) Calculate the total resistance of the circuit shown in Fig. 12.1. total resistance = … Ω [2] (ii) Calculate the current passing through the 6.0 Ω resistor. current = … A [2] (b) The 9.0 V battery is connected in series with a lamp, a variable resistor and a switch. (i) Draw a circuit diagram showing a 9.0 V battery connected in series with a lamp, a variable resistor and a switch. [2] (ii) The variable resistor is used to change the voltage across and the current in the lamp. On Fig. 12.2, sketch a graph showing the current-voltage characteristic of a filament lamp. current voltage Fig. 12.2 [1] (c) Fig. 12.3 shows a circuit containing a thermistor and a lamp in series with an ammeter. A voltmeter is connected in parallel across the thermistor. 9.0 V A V Fig. 12.3 (i) Describe what happens to the readings on the ammeter and voltmeter when the temperature of the thermistor increases. Use the words increases, decreases or stays the same. Each word may be used once, more than once or not at all. ammeter … voltmeter … [1] (ii) Explain why the brightness of the lamp changes as the temperature of the thermistor increases. … … … … … [3] [Total: 11]

11 marks

Mark scheme: 12(a)(i) 1 / RT = 1 / R1 + 1 / R2 or 1 / 12.0 + 1 / 6.0 ; 2 RT = 4.0 () ; 12(a)(ii) (I =) V / R or 9.0 / 6.0 ; 2 1.5 (A) ; 12(b)(i) 2 correct symbols and quantities ; in series ; 12(b)(ii) 1 ; 12(c)(i) (ammeter) increases AND (voltmeter) decreases ; 1 12(c)(ii) the resistance of the thermistor decreases ; 3 the current / pd across the bulb increases ; the bulb receives / converts more energy ;

This question in 0654/43 Oct/Nov 2022

9 (a) Fig. 9.1 shows a simple circuit containing a heater and a thermistor. heater thermistor Fig. 9.1 Use Fig. 9.1 to explain how increasing the temperature of the thermistor changes the power output of the heater. … … … … … … [3] (b) Fig. 9.2 shows an electric kettle. Fig. 9.2 The kettle has a power rating of 3000 W. It takes 336 kJ of energy to heat some water from room temperature to 100 °C. Calculate the time it will take for the kettle to heat the water from room temperature to 100 °C. time = … s [3] (c) Hot water is poured into two similar cups with lids. One cup is black and the other is white. The temperature of the water in each cup is measured every minute for 15 minutes. Fig. 9.3 shows the results. 80.0 70.0 60.0 50.0 temperature / °C 40.0 30.0 A B 20.0 10.0 0 0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 time / minutes Fig. 9.3 State and explain which colour cup gives the results labelled A. A shows the results for the … cup. explanation … … … … [2] (d) Some water is spilt on a table and forms a droplet which acts like a convex lens. Convex lenses can form real and virtual images. Describe the difference between a real image and a virtual image. … … … [1] [Total: 9]

9 marks

Mark scheme: 9(a) resistance of thermistor decreases; 3 current / potential difference, of the heater increases ; power output increases ; 9(b) evidence of unit conversion or 336 000 (J) 3 evidence of (t =) E / P (in any form) or 336 000 / 3000 ; (t =) 112 (s) ; 9(c) white (cup) and 2 white emits less, (IR) radiation / thermal energy, than black ; white / A, cools down more slowly (in 15 minutes) ; 9(d) a real image can be formed on a screen / is formed from real rays of light / is formed from converging rays / AVP ; 1

This question in 0654/42 Feb/March 2023

9 A student investigates how the resistance of a wire changes with length. Fig. 9.1 shows the equipment she uses. cell ammeter 0.66 1.5 V wire ruler crocodile clips Fig. 9.1 (a) The student moves the crocodile clips to change the length of the wire. She measures this length with the ruler and uses the ammeter reading to calculate the resistance of the wire. When the wire is made longer, the reading on the ammeter decreases. Explain why the reading on the ammeter decreases. … … … … [2] (b) Fig. 9.2 shows a length of wire connected in series with another component labelled X. 1.5 V A wire X V Fig. 9.2 (i) State the name of the component labelled X in Fig. 9.2. … [1] (ii) The student uses the component labelled X to vary the potential difference across the length of wire. The student records the potential difference across the wire and the current in the wire. Fig. 9.3 shows her results. 1.75 1.50 1.25 1.00 potential difference / V 0.75 0.50 0.25 0 0 0.20 0.40 0.60 0.80 current / A Fig. 9.3 Use Fig. 9.3 to determine the resistance of the wire. resistance = … Ω [2] (c) The student chooses to use a maximum electromotive force (e.m.f.) of 1.5 V. State the meaning of the term electromotive force (e.m.f.). … … [2] (d) On Fig. 9.4, draw the shape and direction of the magnetic field around the current‑carrying wire. direction of current Fig. 9.4 [2] [Total: 9]

9 marks

Mark scheme: 9(a) (as length increases) resistance increases ; (as resistance increase) current decreases / resistance inversely proportional to resistance ; 2 9(b)(i) variable resistor ; 1 9(b)(ii) (resistance = ) V / I / 1.50/ 0.80 ; (resistance = ) 1.9 () ; 2 9(c) energy supplied / (electrical) work done (by a source) ; driving charge around a (complete) circuit / per (unit) charge around a (complete) circuit ; 2 9(d) concentric circle(s) around wire ; direction shown anti-clockwise ; 2

This question in 0654/41 May/June 2023

9 A student investigates series and parallel circuits using filament lamps. (a) Fig. 9.1 shows the first circuit the student makes using three identical filament lamps. 6.0 V A A V Fig. 9.1 (i) Determine the potential difference shown on the voltmeter. potential difference = … V [1] (ii) Explain why the reading on both ammeters is the same. … … [1] (b) Fig. 9.2 shows the second circuit made by the student using the same three identical filament lamps. 6.0 V 0.9 A A A V Fig. 9.2 One of the ammeters shows a current of 0.9 A as shown in Fig. 9.2. The voltmeter shows a potential difference of 6.0 V. Calculate the resistance of one of the filament lamps. resistance = … Ω [3] (c) The filament lamps emit energy in the form of infrared radiation and visible light. Complete the sentences to compare infrared radiation with visible light. Infrared radiation and visible light are both parts of the … . The wavelength of infrared radiation is … than the wavelength of visible light. The frequency of infrared radiation is … than the frequency of visible light. The speed of infrared radiation and visible light is … . [2] [Total: 7]

7 marks

Mark scheme: 9(a)(i) 2.0 (V) ; 1 9(a)(ii) in a series circuit the current is the same (everywhere) ; 1 9(b) (I =) 0.3 (A) ; (R = ) V / I or 6.0 / 0.3 ; (R = ) 20 () ; 3 9(c) electromagnetic spectrum longer lower the same / 3  108 m / s ;; 2

This question in 0654/42 May/June 2023

3 Fig. 3.1 shows a circuit used by students investigating how the resistance of a metal wire varies with length. (a) The students use an ammeter and a voltmeter to measure the current in and potential difference across the wire. wire Fig. 3.1 (i) Complete Fig. 3.1 to show the correct symbols and positions for the ammeter and the voltmeter. [1] (ii) When the wire is 20 cm long, the ammeter reads 0.80 A and the voltmeter reads 3.0 V. Calculate the resistance of the wire. State the correct unit for your answer. resistance = … unit … [3] (iii) On Fig. 3.2 sketch a graph to show how the resistance of the wire varies with length. [2] resistance length Fig. 3.2 (b) The student notices that when the circuit is left switched on, the wire becomes warm. Describe how conduction transfers thermal energy in the metal wire. … … … … [3] [Total: 9]

9 marks

Mark scheme: 3(a)(i) 1 ; 3(a)(ii) (R =) V ÷ I / 3(.0) ÷ 0.8(0) ; 3 R =) 3.8 ; ohms /  ; 3(a)(iii) 2 positive gradient ; straight line ; 3(b) atoms vibrate ; 3 (idea that) vibrations passed on to next atom ; (idea of) transfer by (free) electrons ;

This question in 0654/42 Oct/Nov 2023

12 Electricity can be generated in different types of power stations. (a) Table 12.1 gives some information about six types of power station. Table 12.1 energy per kg of efficiency of transfer percentage of world type of power station fuel / MJ to electrical energy / % electricity production coal 29 32 37 hydroelectric (HEP) – 90 15 natural gas 45 49 24 nuclear 5.0 × 105 93 10 solar – 21 9 wind – 40 5 (i) Use data from Table 12.1 to explain why electricity generation is negatively impacting the environment. … … … … … [3] (ii) Nuclear power stations are very expensive to build. Apart from cost, state one advantage and one disadvantage of generating electricity using wind compared to nuclear. advantage … … disadvantage … … [2] (iii) Use data from Table 12.1 to calculate the mass of natural gas needed to generate the same electrical energy output as 1 kg of nuclear fuel. mass = … kg [3] (b) A coal power station generates electricity at a voltage of 25 000 V. A transformer is used to step the voltage up to 132 000 V for transmission. (i) The step‑up transformer contains 3000 turns on the primary coil. Calculate the number of turns on the secondary coil. number of turns = … [2] (ii) Explain why electricity is transmitted at a voltage of 132 000 V and not 25 000 V. … … … … [2] [Total: 12]

12 marks

Mark scheme: 12(a)(i) highest percentage of electricity is generated by, coal (and natural gas) / fossil fuels / 61% of production from fossil fuels or coal and natural gas / 37% of production from coal / 24% of production from natural gas ; plus coal / natural gas / fossil fuels, release, carbon dioxide ; cause climate change / global warming / enhanced greenhouse effect ; OR coal / natural gas / fossil fuels, release sulfur dioxide ; causes acid rain ; Question Answer Marks 12(a)(ii) (advantage:) no nuclear, waste / accidents / suitable for small scale / no fuel is used / less set up time / AVP ; (disadvantage:) only works when wind speed is suitable / is less efficient / need lots of turbines (to generate large amounts of electricity) / noise pollution / AVP ; 2 12(a)(iii) (nuclear output E per kg =) 5.0  105  0.93 = 4.65  105 (MJ) ; (gas output E per kg =) 45  0.49 = 22.05 (MJ) ; = 4.65  105 / 22.05 = 21 000 (kg) ; 3 12(b)(i) (Ns =) NpxVs / Vp OR 3000  132 000 / 25 000 ; (Ns =) 16 000 ; 2 12(b)(ii) (increasing the voltage) reduces the current ; less, energy / power / heat, loss ; 2

This question in 0654/42 May/June 2024

9 A student is investigating resistance. (a) Fig. 9.1 shows the circuit made by the student. V I1 I2 2.5 Ω 2.5 Ω 2.5 Ω V1 V2 V3 Fig. 9.1 (i) State how the currents labelled I1 and I2 compare with each other. … [1] (ii) Write an equation showing the relationship between the reading on the voltmeter, V, and the three potential difference values V1, V2 and V3. … [1] (iii) Calculate the total resistance of the circuit. total resistance = … Ω [1] (iv) The reading on the voltmeter in Fig. 9.1 is 1.5 V. Calculate the value of the current I1. State the unit for your answer. current = … unit … [3] (b) The student replaces the three fixed resistors with one thermistor, moves the voltmeter and includes an ammeter. Fig. 9.2 shows the new circuit made by the student. A V Fig. 9.2 (i) The student observes the readings on the ammeter and voltmeter as the thermistor is moved from a warm room into a beaker of ice. State and explain what the student observes on the ammeter and voltmeter. ammeter … … … voltmeter … … … [2] (ii) While the student is conducting the experiment, the ice in the beaker melts into liquid water. Compare the arrangement and motion of molecules in a solid to the arrangement and motion of molecules in a liquid. arrangement … … motion … … [2] [Total: 10]

10 marks

Mark scheme: 9(a)(i) 1 9(a)(ii) V = V1 + V2 + V3 ; 1 9(a)(iii) 7.5 () ; 1 9(a)(iv) (I=) V / R / 1.5 / 7.5 ; (I=) 0.20 ; A / amp / amps / amperes ; 3 9(b)(i) (ammeter:) decreases because the resistance of the thermistor increases ; (voltmeter:) stays the same because it receives the full voltage / owtte ; 2 9(b)(ii) (arrangement:) solid is regular and liquid is random ; (motion:) solid molecules vibrate about a fixed point and liquid molecules can move / slide (past each other) ; 2

This question in 0654/43 May/June 2024

3 A student investigates the properties of graphite. (a) Fig. 3.1 shows a cylinder of graphite. The cylinder is 6.50 cm long and has a cross‑sectional area of 0.300 cm2. 6.50 cm 0.300 cm2 Fig. 3.1 (i) Show that the volume of the cylinder of graphite is 1.95 cm3. [1] (ii) The mass of the cylinder of graphite is 4.40 g. Calculate the density of graphite. density = … g / cm3 [2] (b) The student investigates the resistance of the cylinder of graphite using the circuit shown in Fig. 3.2. 1.5 V A cylinder of graphite V Fig. 3.2 (i) State the reading shown on the voltmeter in Fig. 3.2. reading = … V [1] (ii) The ammeter reads 0.60 A. Use your answer to (b)(i) to calculate the resistance of the cylinder of graphite. resistance = … Ω [2] (iii) A different cylinder of graphite has double the length and double the cross‑sectional area of the cylinder in Fig. 3.2. Explain why the resistance of both cylinders is the same. … … … [2] (c) Graphite is a solid at room temperature. Describe the main method of thermal energy transfer in solids. … … … … [2] [Total: 10]

10 marks

Mark scheme: 3(a)(i) (volume =) 6.5(0)  0.3(00) ; 1 3(a)(ii) m 2 evidence of = or 4.4(0) ÷ 1.95 ; V 2.26 (g / cm3) ; 3(b)(i) 1.5 (V) ; 1 3(b)(ii) evidence of R = V ÷ I or 1.5 ÷ 0.6(0) ; 2 2.5 () ; 3(b)(iii) (idea that) doubling the length doubles the resistance ; 2 (idea that) doubling the (cross-sectional) area halves the resistance ; 3(c) any two from: 2 atoms vibrate ; (idea that) vibrations passed on to next atom ; (idea of) transfer by (free) electrons ;

This question in 0654/41 Oct/Nov 2024

3 A student investigates an NTC thermistor. (a) The student connects the thermistor in series with a cell and an ammeter. The student also connects a voltmeter to measure the potential difference across the thermistor. Fig. 3.1 shows an incomplete circuit diagram of the circuit used by the student. Fig. 3.1 (i) Complete Fig. 3.1. [2] (ii) When the thermistor is at room temperature, the ammeter reads 3.0 A. Calculate the charge that flows through the thermistor in 60 s. State the unit for your answer. charge = … unit … [3] (b) The student places the thermistor into hot water. The student records the values shown by the ammeter and the voltmeter as the temperature of the thermistor increases. Describe how the power output of the thermistor changes as the temperature of the thermistor increases. … … … … … [4] (c) Fig. 3.2 shows the current–voltage characteristic for an ohmic resistor. current 0 0 voltage Fig. 3.2 Explain the shape of the graph shown in Fig. 3.2. … … … … [2] [Total: 11]

11 marks

Mark scheme: 3(a)(i) correct thermistor symbol in correct place ; 2 A and V correct ; 3(a)(ii) (Q =) It or 3  60 ; 3 (Q =) 180 ; C / coulombs ; 3(b) resistance (of thermistor) decreases ; 4 current (in thermistor) increases ; reference to P = IV; power increases ; 3(c) straight line goes / through the origin; 2 Any one from: constant resistance ; current proportional to voltage ; obeys Ohm’s law ; resistance = 1 ÷ gradient ;

This question in 0654/43 Oct/Nov 2024

12 (a) Fig. 12.1 shows a 10 Ω resistor and a resistor R of unknown resistance connected in parallel with a 1.8 V cell. R 10 Ω Fig. 12.1 The current in the cell is 0.32 A. The current in the 10 Ω resistor is 0.18 A. (i) Calculate the current in resistor R. current = … A [1] (ii) State the potential difference across resistor R. potential difference = … V [1] (b) A 40 Ω resistor and a 20 Ω resistor are connected in parallel. Calculate the combined resistance of the two resistors. resistance = … Ω [2] (c) (i) A computer projector has a power rating of 750 W. Mains potential difference is 230 V. Calculate the electric current in the projector. current = … A [2] (ii) The computer projector uses a lens to form an image. In another device, the object is placed between the principal focus and the lens. On Fig. 12.2, draw rays to find the position of the image formed. Use an arrow to represent the image. object F F lens Fig. 12.2 [3] (iii) State a use of the arrangement shown in Fig. 12.2. … [1] [Total: 10]

10 marks

Mark scheme: 12(a)(i) (0.32 – 0.18 = ) 0.14 (A) ; 1 12(a)(ii) 1.8 (V) ; 1 12(b) evidence of R = 40  20 / (40 +20) or 1 / R = 1 / 40 + 1 / 20 ; 2 13 () ; 12(c)(i) I = P / V (in any form) or 750 / 230 ; 2 3.3 (A) ; 12(c)(ii) 3 ;;; 12(c)(iii) magnifying glass ; 1

This question in 0654/41 May/June 2025

12 (a) Fig. 12.1 shows two identical resistors each of resistance 3.8 Ω connected to a cell. P 3.8 Ω 3.8 Ω Q Fig. 12.1 (i) The electromotive force (e.m.f.) of the cell is 1.5 V. Define e.m.f. … … [2] (ii) State the potential difference (p.d.) between points P and Q. State the unit of your answer. p.d. = … unit … [2] (iii) Calculate the combined resistance of the two resistors. resistance = … Ω [1] (b) Fig. 12.2 shows a piece of metal wire with a resistance of 40 Ω along its length. length cross-sectional area Fig. 12.2 A potential difference is applied across the ends of the wire. Describe the process of electrical conduction in the wire. … … … … … [3] (c) A second piece of wire of the same material and length as in Fig. 12.2 has double the diameter. (i) Circle the change, if any, to the cross-sectional area of the wire. halved no change doubled multiplied by 4 [1] (ii) Determine the resistance of this piece of wire. resistance = … Ω [1] [Total: 10]

10 marks

Mark scheme: 12(a)(i) (electrical) work done / energy transferred (by a source); 2 moving a unit charge around a complete/whole circuit; 12(a)(ii) 0.75; 2 V; 12(a)(iii) 7.6 () 1 12(b) delocalised electrons; 3 (electrons) move / flow; from negative potential to positive potential; 12(c)(i) multiplied by 4; 1 12(c)(ii) 10 (); 1

This question in 0654/43 May/June 2025