Electromagnetic effects — Paper 3 · IGCSE Physics 0625

9 A transformer is needed to step down a 240 V a.c. supply to a 12 V a.c. output. For Examiner’s (a) In the space below, draw a labelled diagram of a suitable transformer. [3] Use (b) Explain (i) why the transformer only works on a.c., … … [1] (ii) how the input voltage is changed to an output voltage. … … … [2] (c) The output current is 1.5 A. Calculate (i) the power output, power = … [1] (ii) the energy output in 30 s. energy = … [1]

8 marks

Mark scheme: 9 (a) primary and secondary coils on iron core labelled B1 240 V a.c. to primary, 12 V a.c. to secondary B1 turns ratio shown or stated 20:1, stepdown B1 3 (b) (i) must be constantly changing magnetic field B1 (ii) magnetic field of primary passes through core to secondary B1 magnetic field of secondary cuts coil, induces output B1 3 (c) (i) 18 W A1 (ii) 540 J A1 2 [8]

This question in 0625/31 May/June 2006

11 Fig. 11.1 shows a beam of radiation that contains α-particles, β-particles and γ-rays. The For beam enters a very strong magnetic field shown in symbol form by N and S poles. Examiner’s Use N beam of radiation S Fig. 11.1 Complete the table below. direction of deflection, charge carried by radiation if any radiation, if any α-particles β-particles γ-rays [6]

6 marks

Mark scheme: 11 line1 into paper B1 positive or +2 B1 line 2 out of paper or opposite of line 1 B1 negative or -1 B1 line 3 no deflection B1 no charge B1 6 [6]

This question in 0625/31 May/June 2006

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

9 Electromagnetic induction may be demonstrated using a magnet, a solenoid and other necessary apparatus. (a) Explain what is meant by electromagnetic induction. … … … … [2] (b) In the space below, draw a labelled diagram of the apparatus set up so that electromagnetic induction may be demonstrated. [2] (c) Describe how you would use the apparatus to demonstrate electromagnetic induction. … … … … [2] (d) State two ways of increasing the magnitude of the induced e.m.f. in this experiment. 1. … … 2. … … [2] [Total: 8]

8 marks

Mark scheme: 9 (a) when magnetic field cuts/cut by conductor/wire/coil/solenoid OR change in magnetic field linked with coil etc. B1 current/e.m.f caused B1 (b) solenoid ends connected to meter/lamp note: any sign of a cell gets B0 B1 magnet indicated in suitable position on axis of solenoid B1 (c) insert/withdraw/move magnet into/out of solenoid B1 meter gives reading (as magnet moves) OR watch the meter OR lamp glows B1 (d) move magnet faster ) increase strength of magnet ) any 2 B1+B1 more turns on solenoid ) closer to solenoid ) [Total: 8] IGCSE – October/November 2007 0625 03

This question in 0625/31 Oct/Nov 2007

8 (a) The transformer in Fig. 8.1 is used to convert 240 V a.c. to 6 V a.c. For Examiner’s Use iron core A C D B primary secondary coil coil (480 turns) Fig. 8.1 (i) Using the information above, calculate the number of turns on the secondary coil. number of turns = … [2] (ii) Describe how the transformer works. … … … … … [3] (iii) State one way in which energy is lost from the transformer, and from which part it is lost. … [1] (b) Fig. 8.2 shows a device labelled “IGCSE Transformer”. For Examiner’s Use Fig. 8.2 Study the label on the case of the IGCSE Transformer. (i) What is the output of the device? … [1] (ii) From the information on the case, deduce what other electrical component must be included within the case of the IGCSE Transformer, apart from a transformer. … [1] (c) A transformer supplying electrical energy to a factory changes the 11 000 V a.c. supply to 440 V a.c. for use in the factory. The current in the secondary coil is 200 A. Calculate the current in the primary coil, assuming no losses from the transformer. current = … [2] [Total: 10]

10 marks

Mark scheme: 8 (a) (i) N1/N2 = V1/V2 in any form, symbols, words or numbers C1 12 (turns) [possible unit penalty] A1 (ii) mention of magnetic / electromagnetic field ) ) change of flux linkage / magnetism ) OR field lines being cut ) ) any 3 B1 x 3 Induced current / emf / voltage ) ) Fewer coils in secondary so smaller emf / voltage OR larger current ) (iii) heat in either coil / wires ) eddy currents in core / heat in core ) any 1 B1 magnetic leakage from core ) sound from core/coil ) (b) (i) 12 V d.c. OR low d.c.voltage B1 (ii) diode OR rectifier [Ignore extras unless wrong] B1 (c) V1I1 = V2I2 in any form, or words or numbers OR power in = power out or equivalent C1 8 A A1 [10]

This question in 0625/31 May/June 2010

9 (a) Fig. 9.1 illustrates the left hand rule, which helps when describing the force on a current- For carrying conductor in a magnetic field. Examiner’s Use thumb motion / force first finger second finger Fig. 9.1 One direction has been labelled for you. In each of the other two boxes, write the name of the quantity that direction represents. [1] (b) Fig. 9.2 shows a simple d.c. motor connected to a battery and a switch. N S X switch battery Fig. 9.2 (i) On Fig. 9.2, write in each of the boxes the name of the part of the motor to which For the arrow is pointing. [2] Examiner’s Use (ii) State which way the coil of the motor will rotate when the switch is closed, when viewed from the position X. … [1] (iii) State two things which could be done to increase the speed of rotation of the coil. 1. … 2. … [2] [Total: 6]

6 marks

Mark scheme: 9 (a) first finger – field / magnetism / flux ) second finger – current / charge flow (NOT electron flow) ) both B1 (b) (i) brush OR contact OR sliding connector B1 split ring OR commutator NOT slip ring B1 (ii) clockwise OR right side down OR left side up OR correct arrows on figure NOT turn to the right B1 (iii) more current / more voltage / “stronger battery” / more power ) more turns on coil / more coils ) stronger magnet Ignore bigger magnets ) closer magnet / magnetic poles ) any 2 B1, B1 more magnets ) iron core ) [6] IGCSE – May/June 2010 0625 31

This question in 0625/31 May/June 2010

11 A radium source emits , and radiations. Fig. 11.1 illustrates what happens to these For radiations when they pass through a magnetic field. The left hand beam is actually deviated Examiner’s a great deal less than shown on Fig. 11.1. Use radioactive source Fig. 11.1 (a) On Fig. 11.1, label the three radiations by writing in the boxes provided. [2] (b) State the direction of the magnetic field that gives the deflections shown in Fig. 11.1. … [2] [Total: 4]

4 marks

Mark scheme: 11 (a) γ straight up B1 α to left AND β to right B1 (b) into or out of paper C1 into paper A1 [4]

This question in 0625/32 May/June 2010

11 A radium source emits , and radiations. Fig. 11.1 illustrates what happens to these For radiations when they pass through a magnetic field. The left hand beam is actually deviated Examiner’s a great deal less than shown on Fig. 11.1. Use radioactive source Fig. 11.1 (a) On Fig. 11.1, label the three radiations by writing in the boxes provided. [2] (b) State the direction of the magnetic field that gives the deflections shown in Fig. 11.1. … [2] [Total: 4]

4 marks

Mark scheme: 11 (a) γ straight up B1 α to left AND β to right B1 (b) into or out of paper C1 into paper A1 [4]

This question in 0625/33 May/June 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

8 A coil is wound on a cylindrical cardboard tube and connected to a sensitive centre-zero millivoltmeter. Figs. 8.1, 8.2 and 8.3 show three situations involving the coil and a magnet. (a) On the lines alongside each situation, describe what, if anything, is seen happening on the millivoltmeter. N … magnet inside coil, … mV both moving at same … speed … S … [1] Fig. 8.1 magnet … moving N towards … coil … coil mV stationary … … [1] Fig. 8.2 magnet … stationary N … coil moving … mV towards magnet … … [2] Fig. 8.3 (b) Choose one of the situations in (a) where something is seen happening to the millivoltmeter. For this situation, state three changes which could be made to increase the magnitude of what is seen. 1. … 2. … 3. … [3] [Total: 7]

7 marks

Mark scheme: 8 (a) Fig.8.1 nothing seen/no current/no deflection/no voltage B1 Fig. 8.2 deflection (of needle)/current in mV/voltage induced B1 Fig. 8.3 deflection (of needle)/current in mV/voltage induced (ignore size of deflection) M1 same direction as Fig. 8.2 A1 (b) increase speed B1 increase turns (of wire)/more coils (ignore longer wire) B1 increase magnet strength (ignore larger magnet) B1 [Total: 7] IGCSE – October/November 2010 0625 33

This question in 0625/33 Oct/Nov 2010

9 A simple motor is made in a school laboratory. A coil of wire is mounted on an axle between the poles of a horseshoe magnet, as illustrated in Fig. 9.1. coil B C N S A D springy contacts (brushes) + – battery Fig. 9.1 (a) At the instant illustrated in Fig. 9.1, the coil ABCD is horizontal and the battery is connected as shown. (i) For this position, state the direction of the force on AB and the direction of the motion of AB. force on AB … direction of motion of AB … [1] (ii) Explain why BC does not contribute to the turning force on the coil. … … [1] (b) At the instant when the coil is vertical, the springy contacts do not, in fact, make contact with the ends of the coil. Describe and explain what happens to the coil. … … … … [2] (c) The motor in Fig. 9.1 does not rotate very quickly. The designer of a commercial motor is required to produce a faster-rotating motor. Suggest one change that could be made to increase the speed of the motor. … … [1] [Total: 5]

5 marks

Mark scheme: 9 (a) (i) down both down OR anti-clockwise B1 (ii) BC is parallel to the field/doesn’t cut field or vice-versa/not at angle to field ignore BC not perpendicular to field B1 (b) continues moving/turning NOT reverse/other direction M1 idea of moving things continue moving OR reference to Newton’s Laws OR reference to momentum/KE/inertia NOT reference to force still acting A1 IGCSE – May/June 2011 0625 31 (c) more turns/several coils iron core increase current/voltage stronger magnet smaller air gap any 1 B1 curved poles more efficient brushes poles closer use split-ring commutator [5]

This question in 0625/31 May/June 2011

9 (a) Fig. 9.1 shows a wire, held between the poles of a magnet, carrying a current in the direction of the arrow. current S N Fig. 9.1 (i) On Fig. 9.1, draw an arrow, labelled F, to show the direction of the force acting on the wire. [1] (ii) Explain why the force F acts on the wire. … … [1] (iii) The directions of the current and the magnetic field are both reversed. State the effect on the force F. … [1] (b) Fig. 9.2 shows a negatively charged particle travelling, in a vacuum, into a region where a magnetic field acts. The magnetic field, shown by the crosses, is acting into the paper. – P Fig. 9.2 (i) Draw an arrow, labelled F, to show the direction of the force on the particle at point P where it enters the field. (ii) Describe the path of the particle as it continues to move through the magnetic field. … [2] [Total: 5]

5 marks

Mark scheme: 9 (a) (i) arrow pointing vertically downwards B1 (ii) magnetic fields due to current and magnet interact with each other OR current produces magnetic field. OR wire contains moving charges which experience a force in a magnetic field B1 (iii) direction of force unchanged B1 (b) arrow at P pointing down the page B1 curved path B1 [5]

This question in 0625/32 May/June 2011

9 (a) Fig. 9.1 shows a wire, held between the poles of a magnet, carrying a current in the direction of the arrow. current S N Fig. 9.1 (i) On Fig. 9.1, draw an arrow, labelled F, to show the direction of the force acting on the wire. [1] (ii) Explain why the force F acts on the wire. … … [1] (iii) The directions of the current and the magnetic field are both reversed. State the effect on the force F. … [1] (b) Fig. 9.2 shows a negatively charged particle travelling, in a vacuum, into a region where a magnetic field acts. The magnetic field, shown by the crosses, is acting into the paper. – P Fig. 9.2 (i) Draw an arrow, labelled F, to show the direction of the force on the particle at point P where it enters the field. (ii) Describe the path of the particle as it continues to move through the magnetic field. … [2] [Total: 5]

5 marks

Mark scheme: 9 (a) (i) arrow pointing vertically downwards B1 (ii) magnetic fields due to current and magnet interact with each other OR current produces magnetic field. OR wire contains moving charges which experience a force in a magnetic field B1 (iii) direction of force unchanged B1 (b) arrow at P pointing down the page B1 curved path B1 [5]

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

11 In the laboratory demonstration shown in Fig. 11.1, a copper rod rolls at a steady speed down the sloping parallel copper rails. The rails are in the region of a strong magnetic field that acts vertically downwards. very sensitive centre-zero voltmeter direction V connecting wires of magnetic field copper rod parallel copper rails sloping downwards in direction of arrow Fig. 11.1 (a) Explain why the voltmeter shows a deflection. … … … … [2] (b) State, with reasons, the effect on the voltmeter deflection of the following changes: (i) increasing the strength of the magnetic field, deflection … reason … … … (ii) slightly increasing the slope of the copper rails, deflection … reason … … … (iii) changing the direction of the magnetic field so it is parallel to the copper rails and directed down the slope. deflection … reason … … … [4] [Total: 6]

6 marks

Mark scheme: 11 (a) magnetic flux changes / rod cuts magnetic field B1 emf / voltage induced ignore current induced B1 [2] (b) Mark (i) & (ii) together deflection increases/to R in (i) B1 deflection increases/to R in (ii) B1 correct reason in (i) or (ii) AND consistent with deflection: in (i) or (ii) rate of change of flux (linkage) increases in (i) more (magnetic) field lines cut/stronger (magnetic) field cut in (ii) rod moves faster/field lines cut faster B1 (iii) no deflection AND no (magnetic) field lines cut/no change of flux (linkage) B1 [4]

This question in 0625/32 Oct/Nov 2011

8 Fig. 8.1 shows a simple motor with a rectangular coil that is free to rotate about an axis A1A2. The coil is connected to a battery by brushes B1 and B2. A1 N S + – B1 B2 A2 Fig. 8.1 (a) Brush B1 is connected to the positive terminal of the battery and brush B2 is connected to the negative terminal of the battery. (i) On Fig. 8.1, use an arrow to show the direction of the conventional current in the coil. [1] (ii) State the direction in which the coil rotates, when viewed from the end closest to the brushes. … [1] (b) State what difference, if any, each of the following changes makes to the rotation of the coil: (i) using a battery with a larger potential difference, … (ii) using a coil with several turns of wire carrying the same current as in (a), … (iii) using a stronger magnetic field. … [3] (c) The structure of the motor is very similar to that of an a.c. generator. Use ideas about induction to suggest why the current from the battery falls as the motor speeds up. … … … [1] [Total: 6]

6 marks

Mark scheme: 8 (a) (i) current clockwise when viewed from top B1 (ii) anticlockwise (however expressed) allow ecf from (a)(i) OR down on left and/or up on right B1 (b) (i) faster B1 (ii) faster OR the same B1 (iii) faster B1 (c) (increasing) back / opposing e.m.f. allow an opposing (induced) current B1 [6]

This question in 0625/33 Oct/Nov 2011

10 (a) Fig. 10.1 shows the cross-section of a wire carrying a current into the plane of the paper. For Examiner’s Use Fig. 10.1 On Fig. 10.1, sketch the magnetic field due to the current in the wire. The detail of your sketch should suggest the variation in the strength of the field. Show the direction of the field with arrows. [3] (b) Fig. 10.2 shows part of a model of a d.c. motor. S B axis A C N X D Y Fig. 10.2 A loop of wire ABCD is placed between the poles of a magnet. The loop is free to rotate about the axis shown. There is a current in the loop in the direction indicated by the arrows. (i) On Fig. 10.2, draw arrows to show the directions of the forces acting on side AB and on side CD of the loop. [1] (ii) With the loop in the position shown in Fig. 10.2, explain why the forces on AB and For CD cause the loop to rotate about the axis. Examiner’s Use … … … … [1] (iii) The ends X and Y of the loop are connected to a battery using brushes and a split- ring commutator. State why a split-ring commutator is used. … … … … [2] [Total: 7] Turn over for Question 11

7 marks

Mark scheme: 10 (a) at least 3 concentric circles centred on wire B1 arrows clockwise on each circle / at least one circle B1 spacing of circles increasing as radius increases B1 (b) (i) arrow pointing down on side AB, up on side CD B1 (ii) forces on AB and CD are opposite OR up and down and separated / not in same line (so cause rotation) OR have moments in same sense / direction OR cause couple / torque B1 (iii) to reverse current in loop or keep current in AB or CD in the same direction OR keep current on side near a pole in the same direction when (plane of) coil is vertical OR every half turn OR when AB and CD swap sides B1 so that: rotation continues (in same direction) OR so that rotation doesn’t reverse its direction OR to maintain sense/direction of moments/couple OR coil turns more than half a revolution B1 [Total 7]

This question in 0625/31 May/June 2013

8 Fig. 8.1 shows a vertical current-carrying wire passing through a card at point X. For Examiner’s Use X Y Z card current direction Fig. 8.1 (a) On Fig. 8.1, sketch on the card the pattern of the magnetic field produced by the current in the wire. The detail of your sketch should suggest the variation in the strength of the field. Show the direction of the field with arrows. [3] (b) Using your knowledge of investigating the magnetic field around a bar magnet, suggest an experiment or experiments to confirm that you have drawn the correct pattern and direction in (a). … … … … … … … … [4] (c) A second current-carrying wire is inserted vertically through the card at Y. For Examiner’s Suggest why there is now a force on the wire at X. Use … … … … [2] (d) The wire at Y is moved to Z. It still carries the same current. Tick the appropriate box to indicate whether the force on the wire at X is now smaller, greater or the same. smaller greater same [1] [Total: 10]

10 marks

Mark scheme: 8 (a) at least 3 complete circles/ellipses, roughly centred on X M1 spacing greater as radius increases A1 at least 1 arrow to show clockwise field, no contradiction B1 [3] (b) use of compass/suspended small magnet B1 observe needle/magnet on one field line B1 observe needle/magnet on another field line B1 mark on card OR needle/magnet shows direction of field B1 [4] OR (sprinkle) iron filings o.w.t.t.e. M1 tap card A1 direction/alignment of iron filings show field B1 use compass/suspended small magnet to show field direction B1 (c) wire X/Y is in a magnetic field / any reference to magnetic fields accept description involving poles that clearly implies fields B1 current carrying conductor in field / fields interact/cut/combine/overlap B1 [2] (d) top box only ticked B1 [1] [Total: 10] IGCSE – May/June 2013 0625 32

This question in 0625/32 May/June 2013

9 There is an alternating current in the primary coil of the transformer shown in Fig. 9.1. For Examiner’s soft-iron core Use primary secondary coil coil Fig. 9.1 (a) Tick one box in each line of the table that best describes the magnetic field in the core and the magnetic field in the secondary coil. magnetic field continually continually continually zero increasing and increasing decreasing decreasing soft-iron core secondary coil [2] (b) State and explain the effect on the output from the secondary coil of (i) increasing the voltage across the primary coil, output … explanation … … … … [2] (ii) replacing the alternating current in the primary coil with direct current from a battery. For Examiner’s output … Use explanation … … … … [2] [Total: 6]

6 marks

Mark scheme: 9 (a) first box only ticked in each line 2 × B1 [2] (b) (i) output/V/I/power increases M1 greater (rate of change of) field/flux OR sensible reference to V1 / V2 = N1 / N2 OR V1 proportional to V2 A1 [2] (ii) output/V/I/power zero M1 accept nothing happens NOT no change field/flux does not change ignore transformers only work with a.c./don’t work with d.c. A1 [2] special case for answer about what happens at moment of switching on/off: correct statement of some output etc. for short time M1 change of field/flux A1 [Total: 6]

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

8 (a) Describe an experiment that shows how a magnet can be used to produce a current in For a solenoid by electromagnetic induction. Sketch and label the arrangement of apparatus Examiner’s you would use. Use … … … [3] (b) Fig. 8.1 represents a transformer with primary coil P and secondary coil S, wound on an iron core. There is an alternating current in coil P. iron core P S Fig. 8.1 (i) State what happens in the iron core as a result of the alternating current in P. … … [2] (ii) Tick the box next to the correct description of the current in S. For Examiner’s higher frequency a.c. Use same frequency a.c. lower frequency a.c. rectified d.c. constant d.c. [1] (iii) Coil P has 50 turns of wire, an applied voltage of 12 V, and a current of 0.50 A. Coil S has 200 turns. Calculate the current in S. Assume the transformer is 100 % efficient. current = … [3] [Total: 9]

9 marks

Mark scheme: 8 (a) circuit with solenoid AND galvanometer or ammeter or voltmeter B1 magnet labelled OR poles shown, with any orientation, near solenoid OR inside solenoid B1 appropriate action described e.g. move magnet / solenoid B1 (b) (i) magnetic field (in core) M1 (magnetic field is) alternating / changing / reversing A1 (ii) same frequency a.c. ticked B1 (iii) VS/VP = NS / NP in any form OR (VS =) 12 × 200 / 50 OR 48 (V) C1 VS IS = VPIP in any form OR with numbers C1 (IS =) 12 × 0.50/48 = 0.12 A OR 0.13 A A1 OR IS / IP = NP / NS in any form (C2) (IS =) 0.5 × 50/200 = 0.12 A OR 0.13 A (A1) [Total: 9]

This question in 0625/31 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

10 Fig. 10.1 shows a variable resistor (rheostat) and a solenoid (long coil) connected to a For battery. Examiner’s Use variable resistor solenoid battery Fig. 10.1 The current in the solenoid produces a magnetic field. (a) (i) On Fig. 10.1, draw lines to show the pattern of the magnetic field due to the current. [2] (ii) State the feature of the pattern of the magnetic field lines that indicates the strength of the magnetic field at particular points. … … [1] (b) State and explain the effect on the magnetic field of increasing the resistance of the variable resistor. … … … … [2] (c) In a laboratory vacuum chamber, some current-carrying coils produce a very strong For magnetic field near a source of α-particles. Examiner’s Use Fig. 10.2 shows the arrangement. uniform magnetic _-particle field into source page path of _-particles Fig. 10.2 (i) In the shaded region of Fig. 10.2, draw a possible path for the α-particles in the magnetic field. [2] (ii) State and explain the effect on this path of reversing the current in the coils. … … … [2] [Total: 9]

9 marks

Mark scheme: 10 (a) (i) at least two lines (one left, one right) outside the coil of correct shape or at least two vertical lines inside the coil or two diverging and one central line at top and bottom C1 at least four lines (two left, two right) outside the coil of correct shape or at least two lines (one left, one right) outside the coil of correct shape) and at least two vertical lines inside the coil (crossing or complete loops outside coil gains maximum of 1) A1 [2] (ii) lines closer where field is stronger o.w.t.t.e. or vice versa or spacing of lines B1 [1] (b) reduces (strength of) field B1 (increasing the resistance) reduces the current B1 [2] (c) (i) curved path upwards (might curve back to the left) B1 well-drawn curved path (no straight section and circular by eye) B1 [2] (ii) curves in opposite direction to (c)(i) B1 magnetic field reversed B1 [2] [Total: 9]

This question in 0625/33 Oct/Nov 2013

7 (a) A solenoid connected to a battery produces a magnetic field. The wires are then connected to the battery terminals the other way round. Tick one box in the table to indicate the effect on the magnetic field. decreases but not to zero decreases to zero reverses direction increases stays the same [1] (b) Fig. 7.1 shows a top view of two bar magnets and a vertical rigid conducting rod carrying a current. The direction of the current in the rod is coming out of the paper. S N vertical rod perpendicular to paper S N Fig. 7.1 (i) On Fig. 7.1, draw a single line with an arrow to show the direction of the magnetic field due to the bar magnets at the position of the rod. [2] (ii) State the direction of the force exerted on the vertical rod. … [2] (c) The rod has a mass of 350 g and the resultant force acting on the rod is 0.21 N. The rod is free to move. Calculate the initial acceleration of the rod. acceleration = … [2] [Total: 7]

7 marks

Mark scheme: 7 (a) 3rd box only indicated, reverses direction B1 (b) (i) straight line up / down page B1 arrow pointing down page B1 (ii) to the right or left e.c.f. (b)(i) B1 to the right e.c.f. (b)(i) B1 (c) F=ma in any form or F / m symbols, words or numbers OR final answer 6 × 10–4 m / s2 C1 (a = 0.21 / 0.35 =) 0.6 m / s2 A1 [Total: 7] IGCSE – May/June 2014 0625 32

This question in 0625/32 May/June 2014

11 A battery charger includes a transformer and a rectifier. Fig. 11.1 represents the transformer, consisting of an iron core with two coils P and Q wound on to the core. coil P, 40 000 turns coil Q, 2000 turns iron core Fig. 11.1 P consists of 40 000 turns and Q consists of 2000 turns. When P is connected to a 230 V a.c. supply, there is an e.m.f. across the terminals of Q. (a) (i) Calculate the size of this e.m.f. e.m.f. = … [2] (ii) Explain how this e.m.f. is generated. … … … … … [3] (b) The output of Q is connected to the rectifier circuit. State (i) the name of the circuit component that is used in a rectifier circuit to rectify the a.c. (alternating current), … [1] (ii) the property of this component that is used to rectify the current. … [1] [Total: 7]

7 marks

Mark scheme: 11 (a) (i) (V2=)V1N2 / N2 OR 230 × 2000 / 40 000 C1 11 / 11.5 /12 V A1 (ii) any three from: alternating / changing magnetic field (in core) (magnetic field) transferred (allow conducted) to coil Q changing flux linkage / in Q e.m.f. / voltage induced in Q B3 IGCSE – May/June 2014 0625 33 (b) (i) diode B1 (ii) it conducts in (only) one direction B1 [Total: 7]

This question in 0625/33 May/June 2014

11 (a) Name the process that causes a potential difference across a solenoid due to the movement of a nearby magnet. … [1] (b) Fig. 11.1 shows a solenoid connected to a centre-zero voltmeter, M. A bar magnet is held with its N-pole close to one end of the solenoid. solenoid N M Fig. 11.1 (i) The magnet is pushed into the solenoid, and then brought to rest with its N-pole just inside the solenoid. Describe the movement of the pointer of the meter M. … … [2] (ii) The magnet is now pulled to the left out of the solenoid, at a higher speed than in (i). Compare the movement of the pointer of the meter with that seen in (i). … … [2] [Total: 5]

5 marks

Mark scheme: 11 (a) (i) electromagnetic induction B1 (b) (i) pointer deflects B1 pointer returns to zero B1 (ii) greater deflection (of pointer) B1 pointer deflects in opposite direction and returns to zero OR deflects for shorter time B1 [Total: 5]

This question in 0625/31 Oct/Nov 2014

4 Fig. 4.1 shows a small wind-turbine used to generate electricity. Fig. 4.1 The wind-turbine drives an electric generator. The wind blows with a velocity of 7.0 m / s at right angles to the plane of the turbine. The mass of air passing per second through the turbine is 6.7 kg. (a) (i) Calculate the kinetic energy of the air blown through the turbine per second. kinetic energy = … [2] (ii) Only 8% of this energy is converted to electrical energy. Calculate the power output of the electric generator. power output = … [2] (b) The volume of air passing through the turbine each second is 5.6 m3 (flow rate is 5.6 m3 / s). Calculate the density of the air. density of air = … [2] (c) The turbine turns a generator. Describe the essential action within the generator that produces electricity. … … … [2] [Total: 8]

8 marks

Mark scheme: 4 (a) (i) KE = ½ mv2 in any form OR ½ mv2 C1 (KE = 24.5 × 6.7 =) 164 J OR 160 J A1 (ii) efficiency = output (power) ÷ input (power) OR useful power ÷ input (power) C1 0.08 × candidate’s (a)(i) correctly evaluated A1 (b) use of ρ = m÷V in any form OR m÷V C1 ( ρ = 6.72÷5.6 =) 1.2 kg / m3 A1 (c) rotation/movement of wire/coil OR rotation/movement of magnet B1 consistent with above mark: in magnetic field / between magnetic poles / cutting magnetic field OR in coil / near wire B1 [Total: 8]

This question in 0625/32 Oct/Nov 2014

9 A transformer is used to reduce the voltage of a supply from 120 V a.c. to 12 V a.c. (a) Explain how a transformer works. Your answer should include an explanation of why a transformer would not work with a d.c. supply voltage. … … … … … … … [3] (b) The output current is 1.2 A. (i) Calculate the input current. input current = … [2] (ii) State an assumption you made in your calculation for (b)(i). … … [1] [Total: 6]

6 marks

Mark scheme: 9 (a) changing (magnetic) flux B1 induces e.m.f. in secondary IGNORE induces current B1 no change of flux with constant supply voltage / d.c. B1 (b) (i) I1V1= I 2V2 in any form OR I2V2/V1 C1 (I2 = 1.2 × 12/120 =) 0.12 A A1 (ii) transformer 100% efficient OR has no (heat/energy) losses OR output power = input power B1 [Total: 6]

This question in 0625/32 Oct/Nov 2014

9 Fig. 9.1 shows a simple electric motor with a single rectangular coil between magnetic poles X and Y. coil X Y P Fig. 9.1 (a) (i) Add labels to the empty boxes to the right of Fig. 9.1, to identify the parts indicated. [2] (ii) The coil rotates in a clockwise direction when viewed from point P. State which of the magnetic poles, X or Y, is the N-pole. … [1] (b) (i) Suggest two changes that cause the motor to spin faster. 1. … 2. … [2] (ii) State the effect on the motor of reversing the connections to the battery. … [1] (c) The battery in Fig. 9.1 is replaced with a resistor. The coil is made to rotate by an external mechanism. Explain why there is a current in the resistor. … … … [2] [Total: 8]

8 marks

Mark scheme: 9 (a) (i) Upper box: (split-ring) commutator OR split-ring B1 Lower box: brush(es) OR contact(s) B1 (ii) X (is the N pole) B1 (b) (i) Any two from: B2 Greater current (through coil) OR battery with greater voltage More turns in coil OR coil with greater area Use stronger magnet OR soft-iron core in coil OR bring magnetic poles closer to coil (ii) Coil rotates in opposite direction OR rotates anticlockwise B1 OR rotation reversed (c) Magnetic field is cut (by the wires of the coil) B1 Electromagnetic induction takes place OR Voltage/e.m.f. is induced/produced (causing current in the coil) OR Current is induced (in the coil) B1 [Total: 8]

This question in 0625/32 Feb/March 2015

10 Some older types of oscilloscope contain a cathode-ray tube. (a) In a cathode-ray tube, (i) 1. state the purpose of the heater, … 2. identify the electrode that emits electrons, … 3. identify the electrode that accelerates electrons. … [3] (ii) Explain why the space inside the tube is a vacuum. … … [1] (b) The trace shown in Fig. 10.1 is seen on the screen of the tube. Fig. 10.1 State (i) what causes the up and down movement of the electron beam, … … [2] (ii) what causes the horizontal movement of the electron beam, … … [1] (iii) how the peak-to-peak height of the trace on the screen can be reduced. … [1] [Total: 8]

8 marks

Mark scheme: 10 (a) (i) 1. to heat the cathode/filament OR produces thermionic/electron emission B1 2. cathode / negative terminal B1 3. anode / positive terminal B1 (ii) So that electrons are not obstructed/stopped/deflected (by (air/gas) molecules/particles) OR so filament does not burn out/melt B1 (b) (i) Y-plates OR Voltage applied to Y-plates / Y inputs / Y terminals B1 Alternating voltage/A.C. applied to Y-plates/Y inputs/Y terminals B1 (ii) X-plates OR time-base switched on B1 (iii) Reduce voltage/input/charge/current/field B1 OR Suggestion of change in V / cm setting/gain [Total: 8]

This question in 0625/32 Feb/March 2015

8 (a) Fig. 8.1 shows a bar magnet suspended by a spring over a coil. The coil is connected to a sensitive centre-zero millivoltmeter. spring magnet sensitive coil centre-zero millivoltmeter Fig. 8.1 (i) The lower end of the magnet is pushed down into the upper end of the coil and held at rest. During the movement, an e.m.f. is induced in the coil. The meter shows a deflection to the right and then returns to zero. Explain why this e.m.f. is induced. … … [1] (ii) State what happens to the needle of the meter when 1. the magnet is released from rest and is pulled up by the spring, … [1] 2. the magnet continues to oscillate up and down, moving in and out of the coil with each oscillation. … [1] (b) Fig. 8.2 shows a transformer. 240 V 6.0 V coil P 8000 coil S lampmains turns Fig. 8.2 The primary coil P, connected to the 240 V mains supply, has 8000 turns. The secondary coil S supplies 6.0 V to a lamp. (i) Calculate the number of turns in the secondary coil. number of turns = … [2] (ii) 1. The current in the primary coil is 0.050 A. Calculate the power input to the transformer. power = … [1] 2. 90% of the power input to the transformer is transferred to the lamp. Calculate the current in the lamp. current = … [2] [Total: 8]

8 marks

Mark scheme: 8 (a) (i) (magnetic) field (lines) of magnet cut by turns / coil / wire OR (magnetic) field linked with coil changes B1 (ii) 1 (needle of meter) deflects to the left (and returns to zero) B1 2 (needle of meter) deflects to right and left (alternately) B1 OR to and fro (b) (i) Np/Ns = Vp/Vs in any form OR (Ns =) NpVs/Vp OR 8000 × 6/240 C1 OR (Vp/Vs =) 40 (NS =) 200 A1 (ii) 1 (P = IV = 0.050 × 240 =) 12 W B1 2 0.9 × 12 OR 10.8 OR IsVs = 0.9 IpVp OR Is = 0.9 IpVp /Vs C1 OR 0.9 × 0.05 × 240/6 (Is =) 1.8 A ecf 1. A1 [Total: 8]

This question in 0625/31 May/June 2015

9 Fig. 9.1 represents a transformer. A 240 V coil P coil S a.c. B 8000 turns Fig. 9.1 (a) (i) Name the process by which a changing current in the primary coil P causes a changing current in the secondary coil S. … [1] (ii) Suggest a material used for the coils. Explain why this material is used. … … … [2] (b) The input to the primary coil P is 240 V. This coil has 8000 turns of wire. The voltage obtained between terminals A and B is 12 V. (i) Calculate the number of turns of wire in the secondary coil S. number of turns = … [2] (ii) The resistor connected between the terminals A and B is replaced by four 12 V lamps connected in parallel. The current in each lamp is 1.5 A. Calculate the current in coil P. Assume the transformer is 100% efficient. current = … [3] [Total: 8]

8 marks

Mark scheme: 9 (a) (i) electromagnetic induction OR mutual induction B1 (ii) copper B1 good conductivity OR good conductor B1 (b) (i) NP ÷ Ns = VP ÷ Vs in any form OR NP Vs ÷ VP accept in ratio format C1 400 A1 (ii) (current in secondary =) 4 × 1.5 OR 6.0 (A) C1 IPVP = ISVS in any form OR ISVS ÷ VP C1 0.30 OR 0.3 A A1

This question in 0625/32 May/June 2015

10 A solenoid is held in a vertical position. The solenoid is connected to a sensitive, centre-zero ammeter. A vertical bar magnet is held stationary at position X just above the upper end of the solenoid as shown in Fig. 10.1. S position X magnet N solenoid A position Y magnet Fig. 10.1 The magnet is released and it falls through the solenoid. During the initial stage of the fall, the sensitive ammeter shows a small deflection to the left. (a) Explain why the ammeter shows a deflection. … … [1] (b) The magnet passes the middle point of the solenoid and continues to fall. It reaches position Y. Describe and explain what is observed on the ammeter as the magnet falls from the middle point of the solenoid to position Y. … … … … … … [4] (c) Suggest two changes to the apparatus that would increase the initial deflection of the ammeter. 1. … … 2. … … [2] [Total: 7]

7 marks

Mark scheme: 10 (a) (magnetic) field (lines) of magnet cuts coils (of solenoid) OR (magnetic) field in solenoid changes B1 (b) meter deflects in opposite direction B1 deflection is greater (than initially) OR for shorter time B1 magnet moving faster B1 more field lines cut per second OR opposite pole and direction and end of solenoid B1 (c) any two from: max. B2 • stronger magnet • use a solenoid (of same length) with more turns • use a more sensitive meter • use wires of smaller resistance for solenoid or connecting wires • drop from further up [Total: 7]

This question in 0625/33 May/June 2015

9 Fig. 9.1 shows two separate coils of wire wound around an iron core. primary secondary coil coil iron core Fig. 9.1 An a.c. supply is connected across the primary coil and a 12 V lamp is connected across the secondary coil. The lamp glows with normal brightness. (a) State the name of the device shown in Fig. 9.1. … [1] (b) Explain why there is a current in the lamp. … … … … … [4] (c) (i) The coil connected to the lamp has 450 turns. The e.m.f. of the a.c. supply is 240 V. Calculate the number of turns on the coil connected to the a.c. supply. number of turns = … [2] (ii) A 240 V d.c. supply is used instead of the 240 V a.c. supply. Tick one box to indicate what happens to the lamp. glows more brightly glows with the same brightness glows less brightly does not glow [1] [Total: 8]

8 marks

Mark scheme: 9 (a) (step-down) transformer B1 (b) (alternating current causes) magnetic field in core / iron B1 magnetic field changes / alternates B1 field cuts / links with secondary coil OR secondary coil cuts field B1 e.m.f. / voltage induced (and current flows in lamp) OR induced current (in lamp) B1 (c) (i) V1 / V2 = N1 / N2 in any form OR (N1 =) N2 × V1 / V2 OR 450 × 240 / 12 C1 = 9000 A1 (ii) tick 4th box B1 [Total: 8]

This question in 0625/31 Oct/Nov 2015

10 (a) Fig. 10.1 shows the gap between the N-pole and the S-pole of a magnet. N S Fig. 10.1 The magnetic field in the gap is uniform. On Fig. 10.1, draw four field lines to show the pattern and direction of the magnetic field in the gap. [2] (b) Fig. 10.2 shows a horizontal copper wire PQ between two opposite magnetic poles. Q N S A copper wire P Fig. 10.2 A circuit is made by connecting a sensitive digital ammeter between P and Q. The wire PQ is then moved vertically downwards. (i) State and explain what is observed on the ammeter. … … … … [3] (ii) State what is observed on the ammeter when PQ is moved 1. vertically downwards at a greater speed, … [1] 2. vertically upwards at the same speed as in 1. … [1] [Total: 7]

7 marks

Mark scheme: 10 (a) ≥ 3 horizontal lines in gap by eye B1 ≥ 4 evenly spaced horizontal lines filling ¾ of width of gap AND arrows L to R B1 (b) (i) ammeter deflects / gives a reading OR registers a current B1 wire cuts the field lines o.w.t.t.e. M1 e.m.f. / voltage / current induced / produced / generated A1 (ii) 1 reading / deflection / current increased B1 2 reading / deflection / current reversed ignore magnitude B1 [Total: 7]

This question in 0625/32 Oct/Nov 2015

10 A student uses a bar magnet to distinguish between an unlabelled magnet and an iron bar. (a) Describe how the student identifies which is the magnet and which is the iron bar. … … … … [2] (b) The student suspends the iron bar near to a coil, as shown in Fig. 10.1. The iron bar is free to move. S suspended iron bar coil Fig. 10.1 Describe and explain what happens when the switch S is closed. … … … … … … [3] (c) Fig. 10.2 shows a wire passing through a piece of card. large current card Fig. 10.2 There is a current in the wire in the direction of the arrow. On Fig. 10.3, draw the pattern of the magnetic field lines due to the current in the wire. Include the direction of the field. [3] card wire carrying current into the page Fig. 10.3 [Total: 8]

8 marks

Mark scheme: 10 (a) (bar) magnet is brought close to both ends (of one of unknown bars) B1 either If both ends attract it is an iron bar B1 or If one end repels it is a magnet (b) iron bar moves toward coil B1 any two from: • current in coil • coil becomes an electromagnet B2 • soft iron attracted to coil • iron bar becomes (an induced) magnet (with opposite pole nearest coil) (c) at least one circle centred on wire (by eye) M1 two or more circles centred on wire (by eye) B1 arrow showing clockwise direction on at least one circle B1 [Total: 8]

This question in 0625/32 Feb/March 2016

9 (a) The resistance of a long piece of wire is 6.0 Ω. The potential difference across the wire is 2.0 V. Calculate the current in the wire. current = … A [3] (b) A force acts on a wire carrying a current in a magnetic field. Fig. 9.1 shows the direction of the current in the wire and the direction of the force acting on the wire. wire current N S direction of force Fig. 9.1 (i) On Fig. 9.1, draw arrows to indicate the direction of the magnetic field. [1] (ii) The magnetic field is reversed. State what happens, if anything, to the direction of the force on the wire. … [1] (c) Fig. 9.2 shows a current-carrying coil in a magnetic field. magnet axle N N coil to + magnet S S – battery axle Fig. 9.2 The coil starts to turn about its axle. (i) State two ways of increasing the turning effect on the coil. 1. … 2. … [2] (ii) Describe and explain the effect of reversing the connections to the battery. … … … … [2] [Total: 9]

9 marks

Mark scheme: 9(a) V = I × R OR V ÷ R in words, numbers or symbols 2.0 ÷ 6.0 0.33 (A) B1 B1 B1 9(b)(i) arrows indicating field drawn from N to S B1 9(b)(ii) force upwards / reverses B1 9(c)(i) any two from: increase current in the coil increase the strength of the magnets or magnetic field increase the number of turns in the coil B2 9(c)(ii) force on (each side of) coil or turning effect is in opposite direction or coil turns in opposite direction (because) current (through motor) is in opposite direction B1 B1 Total: 9

This question in 0625/32 May/June 2016

10 Fig. 10.1 shows the charger for a laptop computer. charger Fig. 10.1 The charger contains a transformer. (a) The voltage across the primary coil of the transformer is 230 V. The primary coil has 4995 turns and the secondary coil has 555 turns. Calculate the output voltage of the transformer. output voltage = … V [3] (b) State the term used to describe this type of transformer. … [1] [Total: 4]

4 marks

Mark scheme: 10(a) 230 / V s = 4995 ÷ 555 or Vs = 230 ÷ 9 Vs = (555 ÷ 4995) × 230 25.6 (V) C1 C1 A1 10(b) step-down (transformer) B1 Total: 4

This question in 0625/32 May/June 2016

9 (a) The resistance of a long piece of wire is 6.0 Ω. The potential difference across the wire is 2.0 V. Calculate the current in the wire. current = … A [3] (b) A force acts on a wire carrying a current in a magnetic field. Fig. 9.1 shows the direction of the current in the wire and the direction of the force acting on the wire. wire current N S direction of force Fig. 9.1 (i) On Fig. 9.1, draw arrows to indicate the direction of the magnetic field. [1] (ii) The magnetic field is reversed. State what happens, if anything, to the direction of the force on the wire. … [1] (c) Fig. 9.2 shows a current-carrying coil in a magnetic field. magnet axle N N coil to + magnet S S – battery axle Fig. 9.2 The coil starts to turn about its axle. (i) State two ways of increasing the turning effect on the coil. 1. … 2. … [2] (ii) Describe and explain the effect of reversing the connections to the battery. … … … … [2] [Total: 9]

9 marks

Mark scheme: 9(a) V = I × R OR V ÷ R in words, numbers or symbols 2.0 ÷ 6.0 0.33 (A) B1 B1 B1 9(b)(i) arrows indicating field drawn from N to S B1 9(b)(ii) force upwards / reverses B1 9(c)(i) any two from: increase current in the coil increase the strength of the magnets or magnetic field increase the number of turns in the coil B2 9(c)(ii) force on (each side of) coil or turning effect is in opposite direction or coil turns in opposite direction (because) current (through motor) is in opposite direction B1 B1 Total: 9

This question in 0625/33 May/June 2016

10 Fig. 10.1 shows the charger for a laptop computer. charger Fig. 10.1 The charger contains a transformer. (a) The voltage across the primary coil of the transformer is 230 V. The primary coil has 4995 turns and the secondary coil has 555 turns. Calculate the output voltage of the transformer. output voltage = … V [3] (b) State the term used to describe this type of transformer. … [1] [Total: 4]

4 marks

Mark scheme: 10(a) 230 / V s = 4995 ÷ 555 or Vs = 230 ÷ 9 Vs = (555 ÷ 4995) × 230 25.6 (V) C1 C1 A1 10(b) step-down (transformer) B1 Total: 4

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

12 Fig. 12.1 shows a coil of wire between the poles of a magnet. magnet B C N S A D springy contacts (brushes) Fig. 12.1 (a) (i) On Fig. 12.1, complete the circuit diagram by adding a battery and a switch in series with the coil. [2] (ii) When the switch is closed there is a current in the coil which produces a turning effect. State three ways of increasing the turning effect on the coil. 1. … 2. … 3. … [3] (b) (i) A student has a coil of wire, a magnet and a galvanometer. Describe an experiment using this equipment to demonstrate electromagnetic induction. You may draw a diagram to show the arrangement. … … … … … [3] (ii) The strength of the magnetic field affects the size of the induced e.m.f. Name two other factors that also affect the size of the induced e.m.f. 1. … 2. … [2] [Total: 10]

10 marks

Mark scheme: 12(a)(i) correct symbols for battery AND switch B1 connected in series with coil B1 12(a)(ii) increasing turns on coil B1 increasing the current B1 increasing the strength of the magnetic field B1 12(b)(i) coil in series with galvanometer B1 magnet moved relative to coil B1 deflection on galvanometer B1 12(b)(ii) more OR less coils OR number of coils B1 faster OR slower movement OR speed of magnet OR coil B1 Total: 10

This question in 0625/33 Oct/Nov 2016

11 An electrical conductor is placed between the poles of a magnet as shown in Fig. 11.1. 0 electrical conductor S pole N pole Fig. 11.1 (a) State a material from which an electrical conductor can be made. … [1] (b) (i) A centre-zero meter measures the electromotive force (e.m.f.) across the conductor. State the unit of e.m.f. unit = … [1] (ii) State what, if anything, is shown by the centre-zero meter when the conductor is moved. • horizontally, from side-to-side, between the poles of the magnet, … • vertically, up-and-down, between the poles of the magnet. … [3] (c) State two factors that affect the size of the e.m.f. across the conductor. 1 … 2 … [2] [Total: 7]

7 marks

Mark scheme: 11(a) metal B1 11(b)(i) volt OR V OR mV B1 11(b)(ii) 1 Nothing owtte B1 2 pointer deflects / moves B1 backwards and forwards owtte B1 11(c) 1 strength of magnet B1 2 rate of (relative) movement B1 Total: 7

This question in 0625/32 Feb/March 2017

12 A student demonstrates electromagnetic induction. (a) Describe how to demonstrate electromagnetic induction using a magnet, a coil of wire and a sensitive ammeter. You may include a diagram. … … … … [3] (b) State two factors that affect the size of an induced electromotive force (e.m.f.) 1. … 2. … [2] [Total: 5]

5 marks

Mark scheme: 12(a) coil of wire connected in series with (sensitive) ammeter B1 magnet moves relative to coil B1 meter indicates/measures (induced) current B1 12(b) Any two from: B2 speed of movement owtte strength of magnet number of coils/turns per metre Total: 5

This question in 0625/31 May/June 2017

9 Fig. 9.1 shows a current-carrying coil in a magnetic field. coil B C current N S A D F connections to battery + – battery Fig. 9.1 The direction of the current in side AB of the coil is labelled. The force F on side AB is also labelled. (a) On Fig. 9.1, draw • an arrow labelled X, on side CD, to show the direction of the current in this side of the coil, • an arrow labelled P, to show the direction of the force on CD. [2] (b) Give two ways of increasing the forces F and P on the sides of the coil. 1. … … 2. … … [2] (c) (i) Name the particles that flow in the metal wire of the coil. … [1] (ii) The wire of the coil is replaced by a thinner wire. This wire is the same length and is made of the same metal. State and explain how this changes the current in the coil. … … … [2] [Total: 7]

7 marks

Mark scheme: 9(a) arrow drawn pointing from C to D B1 arrow on /near side CD pointing upwards B1 9(b) any 2 from: increase (size of) current increase strength of magnet increase number of turns in coil B2 9(c)(i) electrons B1 9(c)(ii) current is smaller B1 (as) resistance of coil/wire is greater B1 Total: 7

This question in 0625/32 May/June 2017

11 (a) The plug for a television contains a fuse. Explain the purpose of the fuse. … … … [2] (b) The circuit of the television includes transformers. (i) State the metal used for the two coils of each transformer. … [1] (ii) One transformer has an input voltage of 224 V and an output voltage of 16.0 V. The input coil contains 308 turns. Calculate the number of turns on the output coil. number of turns = … [3] [Total: 6]

6 marks

Mark scheme: 11(a) protects circuit if current too large B2 11(b)(i) copper B1 11(b)(ii) S S P P N V N V = in any form C1 S S 16 N 224 308 or 224 308 16 N = = C1 22 (turns) A1 Total: 6

This question in 0625/32 May/June 2017

10 A transformer is connected to a 240 V supply. It is used to provide the correct voltage for the motor in an electric drill. Fig. 10.1 shows the circuit. 240 V coil X coil Y M Fig. 10.1 (a) The transformer consists of two coils, labelled coil X and coil Y. State the name of each coil. X … Y … [1] (b) Coil X has 6400 turns and coil Y has 400 turns. Calculate the voltage provided to the motor of the electric drill. voltage = … V [3] [Total: 4]

4 marks

Mark scheme: 10(a) (coil X) primary (coil Y) secondary B1 10(b) Ns/ Np = Vs / Vp in any form C1 240 / Vs = 6400 / 400 OR Vs/ 240 = 400 / 6400 C1 15 (V) A1 Total: 4

This question in 0625/33 May/June 2017

10 (a) A student investigates electromagnetic induction. Fig. 10.1 shows the arrangement she uses. wire S N 0 –2 +2 sensitive centre-zero meter Fig. 10.1 When the student holds the wire stationary, as shown in Fig. 10.1, the reading on the meter is zero. She moves the wire down between the poles of the magnet. Then she holds it stationary and then moves it up. (i) The meter measures the size and direction of the induced electromotive force (e.m.f.). On Fig. 10.2, draw the position of the pointer on the meter at each stage. One has been done for you. 0 0 0 –2 +2 –2 +2 –2 +2 wire moving down wire stationary wire moving up [2] Fig. 10.2 (ii) Describe how the student could increase the size of the induced electromotive force (e.m.f.). … … … [2] (b) A transformer is used near a power station. There are 60 turns on the input coil and 660 turns on the output coil. The input voltage is 25 000 V. Calculate the output voltage. output voltage = … V [3] (c) State two advantages of high-voltage transmission of electrical energy. 1. … 2. … [2] [Total: 9]

9 marks

Mark scheme: 10(a)(i) Pointer(s) not on zero B1 Pointers in opposite directions B1 10(a)(ii) Any 2 from: Increase speed of wire B2 wrap wire into a coil Increase strength of magnet 10(b) Ns/Np = Vs/Vp OR 660 ÷ 60 = Vs ÷ 25 000 C1 Vs or output voltage = (660 / 60) × 25 000 = 11 × 25 000 C1 275 000 (V) A1 10(c) Any 2 from: Reduced energy / power losses B2 Smaller conductors needed Reduced voltage drop (across cable)

This question in 0625/31 Oct/Nov 2017

11 Fig. 11.1 shows a charger for a mobile (cell) phone. The charger contains a transformer. Fig. 11.1 (a) The primary coil of the transformer has 900 turns and the secondary coil has 49 turns. The input voltage to the transformer is 220 V. Calculate the output voltage. output voltage = … V [3] (b) State the name of the metal used to make the coils of the transformer. … [1] (c) A transformer uses an alternating current (a.c.). Describe the difference between alternating current (a.c.) and direct current (d.c.). … … … [1] [Total: 5]

5 marks

Mark scheme: 11(a) N1/ N2 = V1 / V2 C1 (49 / 900) × 220 OR use of ratios seen C1 11.98 OR 12 (V) A1 11(b) copper B1 11(c) d.c. is in one direction only / a.c. changes direction B1

This question in 0625/32 Oct/Nov 2017

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

11 Fig. 11.1 represents a transformer. P a.c. input Q primary coil Fig. 11.1 (a) (i) State the name of the part of the transformer labelled Q in Fig. 11.1. … [1] (ii) In Fig. 11.1, part P is made from a metal. 1. State the metal used to make part P. … 2. State the term given to part P. … [2] (iii) There is an alternating current (a.c.) in the primary coil. Describe what this current produces in part P. … … [2] (iv) Complete the sentence using terms from the box. more fewer step-up step-down When there are … turns in the primary coil than in Q, the device is called a … transformer. [1] (b) The high-voltage transmission of electricity uses transformers. Describe two advantages of transmitting electricity at high voltages rather than at low voltages. 1. … … 2. … … [2] [Total: 8]

8 marks

Mark scheme: 11(a)(i) (Q is the) secondary/output (coil) 1 11(a)(ii) 1. (soft–) iron 1 2. core 1 11(a)(iii) magnetic field OR e.m.f. OR magnet 1 changing OR alternating 1 11(a)(iv) EITHER more «AND step-down OR fewer «AND step-up 1 11(b) any two from: smaller current (in wires) smaller drop in p.d./voltage (across cables) smaller heating effect less energy wasted/more efficient thinner cables can be used fewer pylons neededl (electricity) can be transmitted over long(er) distances 2

This question in 0625/32 May/June 2018

11 Fig. 11.1 shows a coil (solenoid) wrapped around a plastic tube. There is a current in the coil. The arrows show the direction of the current in the coil. plastic tube Fig. 11.1 (a) On Fig. 11.1, draw the pattern of the magnetic field lines around the coil. Add arrows to show the direction of the magnetic field. [3] (b) A long soft iron bar is placed inside the plastic tube. There is a current in the coil. This forms a device. State the name of the device. … [1] (c) Fig. 11.2 shows a relay operated by switch S. springy metal M A contacts B pivot insulator soft iron armature soft iron core coil of wire S Fig. 11.2 Using Fig. 11.2, describe how closing the switch, S, causes the electric motor to operate. … … … … … … … … [4] [Total: 8]

8 marks

Mark scheme: 11(a) Correctly-drawn magnetic field around coil 1 lines to start and end near coil/tube 1 field line arrows point towards left hand of coil 1 11(b) electromagnet 1 11(c) (when switch S1 is closed there is a) current in the coil (of wire) 1 (soft) iron (core) becomes magnetised/magnetic field created 1 soft iron armature attracted (to core) 1 contacts/A and B close/(motor) circuit completed/current in motor circuit 1

This question in 0625/33 May/June 2018

11 (a) A student has a model electric railway. The model railway uses a step-down transformer. The input voltage is 230 V. The transformer has 1710 turns on the input coil and 90 turns on the output coil. Calculate the output voltage of the transformer. output voltage = … V [3] (b) A step-up transformer is used to increase voltage. Step-up transformers and step-down transformers have different coil arrangements. Describe the differences in the coil arrangement for the two types of transformer. … … … … … [2] (c) Explain the advantage of transmitting electricity at high voltages, rather than at low voltages. … … … … [2] [Total: 7]

7 marks

Mark scheme: 11(a) (Vp / Vs) = (Np / Ns) in any form C1 230 / Vs = 1710 / 90 or Vs = (230 × 90) / 1710 OR Vs = 230 / 19 C1 12 (V) A1 11(b) In a step-down transformer there are fewer turns on secondary / output coil (than on primary / input coil) In a step-up transformer there are more turns on secondary / output coil (than on primary / input coil) B2 11(c) less energy / power wasted (in cables ) / more efficient (transmission) B1 And any one from: (because) smaller current (in transmission cables) (and so) smaller heating effect (in transmission cables) (and so) thinner cables can be used (which are cheaper) B1

This question in 0625/31 Oct/Nov 2018

9 A student fits an electrical generator to a bicycle. When the front wheel turns, a magnet rotates between two coils of wire. A lamp is connected to the coils of wire. When the magnet is rotating, the lamp is lit. Fig. 9.1 shows the magnet, the coils of wire and the lamp. N S lamp Fig. 9.1 (a) Describe and explain how rotating the magnet causes the lamp to light. … … … … [3] (b) State three ways of increasing the brightness of the bicycle lamp. 1. … 2. … 3. … [3] (c) The generator provides an a.c. supply for the lamp. (i) State the meaning of the term a.c. … [1] (ii) Describe how a.c. differs from d.c. … … [1] [Total: 8]

8 marks

Mark scheme: 9(a) magnetic field (of magnet) B1 changes / cuts coil / linked to coil B1 induces / causes / produces / generates an emf / voltage / current OR electromagnetic induction B1 9(b) stronger magnet more turns on coil(s) turn magnet at higher speed B3 9(c)(i) alternating (current) B1 9(c)(ii) a.c. changes direction OR d.c one direction only B1

This question in 0625/32 Oct/Nov 2018

11 (a) A long straight wire passes through a piece of card. There is a current in the wire, as shown in Fig. 11.1. current card Fig. 11.1 Fig. 11.2 shows the view of the card from above. The current is into the page. card magnetic field line Fig. 11.2 The current in the wire produces a magnetic field around the wire. One magnetic field line is drawn. On Fig. 11.2, draw two more magnetic field lines around the wire. Show the direction of the magnetic field by drawing an arrow on each field line. [2] (b) Fig. 11.3 shows the circuit for an electric bell. contact screw soft iron hammer armature springy metal strip coils of wire bell switch Fig. 11.3 Explain how the circuit causes the hammer to hit the bell repeatedly when the switch is closed. Use your ideas about circuits and electromagnets. … … … … … … … [5] [Total: 7]

7 marks

Mark scheme: 11(a) two roughly circular lines drawn B1 arrow showing clockwise direction B1 11(b) any 5 from: current in circuit / coil(s) coil becomes electromagnet owtte (coil / electromagnet) attracts (soft iron) armature (so) hammer hits gong circuit is broken (at A / contact screw) electromagnet loses magnetic field / stops working armature springs back cycle repeats B5

This question in 0625/32 Oct/Nov 2018

3 Fig. 3.1 shows devices that generate electricity. Fig. 3.1 (a) Describe how the devices shown in Fig. 3.1 generate electrical energy. … … … … [3] (b) Describe the advantages and disadvantages of generating electrical energy by using a coal-fired power station compared with the devices shown in Fig. 3.1. … … … … … … … … [4] [Total: 7]

7 marks

Mark scheme: 3(a) Kinetic OR movement energy from wind OR moving air B1 turns turbine B1 turbine turns generator (to generate electricity) B1 3(b) Any two advantages from: reliable supply of electricity owtte large amount of electrical energy produced / power output plentiful supply of fuel B2 Any two disadvantages from: non-renewable (energy source) greenhouse gases / carbon dioxide produced / increases global warming contributes to atmospheric / air pollution / acid rain B2

This question in 0625/33 Oct/Nov 2018

8 Fig. 8.1 shows a sheet of paper. A bar magnet is underneath the paper. A student sprinkles iron filings onto the paper. paper position of magnet under paper Fig. 8.1 (a) On Fig. 8.1 Label the position of each pole of the magnet. Use the label N for the north pole and S • for the south pole. Draw one magnetic field line above the magnet and draw one magnetic field line below • the magnet. Add one arrow to show the direction of the magnetic field. • [4] (b) A student places a soft iron rod inside a coil of insulated wire. The coil is connected to a battery, as shown in Fig. 8.2. soft iron rod battery coil of insulated wire switch Fig. 8.2 (i) State the name given to the device shown in Fig. 8.2. … [1] (ii) The student puts one end of the device in Fig. 8.2 just above a pile of iron filings. He closes the switch for a short time and then opens it again. Describe the effect this has on the iron filings. … … [1] (iii) The student removes the soft iron rod and replaces it with a steel rod. He puts one end of the steel rod just above the pile of iron filings. He closes the switch for a short time and then opens it again. Describe the effect this has on the iron fillings. … … … [1] [Total: 7]

7 marks

Mark scheme: 8(a) N and S labelled at either end of magnet correct field line shown above magnet correct field line shown below magnet field points in direction N to S B4 8(b)(i) electromagnet B1 8(b)(ii) (soft iron) filings attracted, but (most) fall off when switch opened B1 8(b)(iii) (steel) (most / more / they) remain attached when switch opened B1

This question in 0625/33 Oct/Nov 2018

11 (a) Fig. 11.1 shows a simple electric motor. X N Y S W Z brush contact Fig. 11.1 (i) There is a current in the coil WXYZ. The direction of this current is shown by the arrows. On Fig. 11.1, draw an arrow to show the direction of the force acting on side WX and an arrow to show the direction of the force acting on side YZ. [1] (ii) State three ways of increasing the turning effect of the motor. 1. … 2. … 3. … [3] (b) In a home, a step-down transformer reduces the mains voltage of 225 V to 4.5 V. The transformer has 4000 turns on the primary coil. Calculate the number of turns on the secondary coil. number of turns = … [3] [Total: 7]

7 marks

Mark scheme: 11(a)(i) arrow up from side WX of coil AND an arrow down from side YZ of coil B1 11(a)(ii) any three from: stronger / more powerful magnets smaller gap between coil and magnet(s) larger current in coil more coils / turns B3 11(b) Vp/ Vs = Np / Ns OR ratio used C1 4000 ÷ (225 ÷ 4.5) OR (4000 × 4.5) ÷ 225 OR 4000 ÷ 50 C1 80 A1

This question in 0625/33 Oct/Nov 2018

11 Fig. 11.1 shows a relay. contacts pivot to secondary circuit armature C primary circuit Fig. 11.1 (a) The statements describe the action of a relay. They are not in the correct order. P Current in the coil creates an electromagnet. Q Secondary circuit is completed. R Armature pivots, closing the contacts. S Part C attracts the armature. T The switch in the primary circuit is closed. Place the statements in the correct order. One has been done for you. S [3] (b) Fig. 11.1 includes the part labelled C, which is made from a metal. State the name of the metal and explain why this metal is used in the electromagnet. metal … explanation … … [2] [Total: 5]

5 marks

Mark scheme: 11(a) T P (S) R Q B3 11(b) (soft) iron B1 (forms a) temporary magnet B1

This question in 0625/32 Feb/March 2019

11 (a) Fig. 11.1 shows in each of the diagrams a current-carrying conductor and a magnetic field pattern. current-carrying current-carrying current-carrying conductor conductor conductor A B C Fig. 11.1 State the diagram which correctly shows the magnetic field around a current-carrying conductor. … [1] (b) Fig. 11.2 shows three pieces of equipment. coil S N bar magnet coil with 100 sensitive centre-zero turns of wire meter Fig. 11.2 (i) Describe how to generate and detect an electromotive force (e.m.f.) using the equipment in Fig. 11.2. You may draw a diagram. … … … … [3] (ii) Describe two changes that will generate a larger e.m.f. using similar equipment to that in Fig. 11.2. … … … … [2] (c) A student connects a lamp and centre-zero galvanometer in series with a generator, as shown in Fig. 11.3. lamp centre-zero generator G galvanometer Fig. 11.3 The student observes the galvanometer needle moving from side-to-side repeatedly. Explain why the needle moves in this way. … … … [1] [Total: 7]

7 marks

Mark scheme: 11(a) (diagram) A B1 11(b)(i) connect coil to (centre zero) meter B1 move magnet in OR / AND out of coil B1 (observe) deflection on meter B1 11(b)(ii) any two from: use stronger magnet move magnet faster more turns on coil OR use more than 100 turns B2 11(c) (generator produces) alternating current OR direction of current keeps changing B1

This question in 0625/31 May/June 2019

11 Fig. 11.1 shows a transformer that can provide two different output voltages from a 240 volt mains a.c. supply. P 240 V Q a.c. R primary coil metal core secondary coil 5000 turns Fig. 11.1 In the transformer, the primary coil has 5000 turns. The secondary coil has 250 turns between P and R. (a) State the term used to describe this type of transformer. … [1] (b) The primary and secondary coils are mounted on a metal core. State the metal used for the core and explain why it is suitable. metal … explanation … … [2] (c) (i) The secondary coil has 125 turns between P and Q. Calculate the output voltage between connections P and Q. voltage = … V [3] (ii) Compare the output voltage between P and Q with the output voltage between P and R. Explain your answer. comparison … explanation … [2]

8 marks

Mark scheme: 11(a) step-down (transformer) B1 11(b) (soft) iron B1 forms a temporary magnet B1 11(c)(i) Vp/Vs = Np/Ns OR ratio used C1 240 × (125 ÷ 5000) C1 (PQ = ) 6 (V) A1 11(c)(ii) (PR =) 12 (V) / double the value in (c)(i) (PQ) B1 twice as many turns between P and R (as P and Q) B1

This question in 0625/32 May/June 2019

10 Fig. 10.1 shows a desktop computer. The computer is connected to a mains supply by a plug containing a fuse. Fig. 10.1 (a) The computer has a metal case. A fault occurs and a live wire touches the metal case. Explain how an earth wire and the fuse in the plug protect the user. … … … … … [3] (b) The computer contains a transformer. The input voltage to the transformer is 240 V and the output voltage is 12.0 V. The input coil of the transformer has 3000 turns. Calculate the number of turns on the output coil. number of turns = … [3] [Total: 6]

6 marks

Mark scheme: 10(a) any 3 from: earth wire is connected to metal case earth wire has low resistance large current in earth wire fuse in live wire fuse (heats up and) melts this disconnects case/computer/circuit from supply ( and so protects user) B3 10(b) (Vp / Vs ) = (Np / Ns ) in any form C1 240 / 12 = 3000 / Ns OR Ns = 3000 × (12/240) OR Ns = 3000 / 20 C1 150 (turns) A1

This question in 0625/33 May/June 2019

12 A student uses the equipment shown in Fig. 12.1. coil S N magnet pointer sensitive centre-zero milli-voltmeter Fig. 12.1 The student moves the magnet to the right into the coil and then holds the magnet stationary for a few seconds. The pointer deflects to the right and then returns to the centre. The student then moves the magnet to the left so that it is completely out of the coil and moves it far away from the coil. (a) Describe how the pointer moves when the student moves the magnet out of the coil. … … [2] (b) Explain why the pointer behaves as described in (a). … … … … … [3] [Total: 5]

5 marks

Mark scheme: 12(a) pointer deflects to the left B1 (then pointer) returns to zero reading B1 12(b) any three from: (magnet has a) magnetic field conductor/coil cuts magnetic field (this) induces or produces emf/voltage/p.d. in the conductor/coil (so reading on meter) no cutting of field when far from coil (so no reading on meter) B3

This question in 0625/33 May/June 2019

11 A student is experimenting with electromagnetic effects. (a) Describe an experiment, using any standard laboratory equipment, to demonstrate electromagnetic induction. You may draw a diagram. … … … … [3] (b) Fig. 11.1 shows a transformer connected to an input voltage of 12 V a.c. core output input 12 V a.c. voltage voltage primary coil secondary coil 20 turns 300 turns Fig. 11.1 (i) State the name of a suitable material for the core of the transformer. … [1] (ii) Explain how the diagram in Fig. 11.1 shows a step-up transformer. … … [1] (iii) Using the information in Fig. 11.1, calculate the output voltage of the transformer. output voltage = … V [3] [Total: 8]

8 marks

Mark scheme: 11(a) relative movement (between conductor and magnetic field) And any two from: connect conductor/coil to (sensitive) meter use of magnet/magnetic field B1 deflection on meter (indicates emf) OR voltage generated OR current in conductor B2 11(b)(i) (soft-) iron B1 11(b)(ii) more turns on output coil (than input coil) ora B1 11(b)(iii) Vs / Vp = Ns / Np in any form C1 Vs / 12 = 300 / 20 OR Vs = (300 / 20) × 12 OR Vs = 15 × 12 OR 12 / 20 = ? / 300 C1 180 (V) A1

This question in 0625/31 Oct/Nov 2019

11 (a) Identify which of the following metals can be permanently magnetised. Place a tick (3) in the box next to any correct metal. aluminium copper steel tungsten [1] (b) Two metal rods are thought to be permanent magnets. Describe the test you would carry out to confirm that both rods are permanent magnets. … … … [2] (c) (i) Describe how to make an electromagnet. You may draw a labelled diagram to help your answer. … … … … [3] (ii) Suggest two factors that affect the strength of the magnetic field of an electromagnet. 1 … 2 … [2] [Total: 8]

8 marks

Mark scheme: 11(a) 3rd box ticked steel B1 11(b) place ends/poles together B1 repulsion (takes place) B1 11(c)(i) coil of wire B1 iron rod inside B1 coil connected to an (electrical) power supply OR current in coil B1 11(c)(ii) number of turns (in coil) B1 current (in coil) B1

This question in 0625/32 Oct/Nov 2019

11 Fig. 11.1 shows a diagram of an electrical device. The diagram is not complete. The coil rotates in a magnetic field when connected to a d.c. power supply. coil magnet S N Y X Fig. 11.1 (a) (i) Explain the meaning of the term d.c. … … [1] (ii) Complete the diagram in Fig. 11.1 by drawing the symbols for two cells in series and a switch to make a circuit. [2] (b) (i) State the name of the electrical device shown in Fig. 11.1. … [1] (ii) State two changes to the electrical device that will make the coil in the device rotate faster. 1. … 2. … [2] [Total: 6]

6 marks

Mark scheme: 11(a)(i) current is in one direction B1 11(a)(ii) symbols for two cells connected in series symbol for a switch B1 B1 11(b)(i) motor B1 11(b)(ii) any two from: increasing number of turns on coil increasing the current (in the coil) increasing the strength of the magnetic field B2

This question in 0625/33 Oct/Nov 2019

5 Fig. 5.1 shows a wind turbine. Fig. 5.1 (a) Describe how the wind turbine produces electrical energy. … … … … [3] (b) Wind turbines are used in many countries to replace coal-fired power stations. (i) State one disadvantage of using wind turbines compared to coal-fired power stations. … … [1] (ii) State two advantages of using wind turbines instead of coal-fired power stations. 1. … 2. … [2] [Total: 6]

6 marks

Mark scheme: 5(a) Any three from: kinetic energy (of wind / air) turns / drives turbine (blades) (turbine blades) turn generator coil turns in magnetic field B3 5(b)(i) any one from: a dilute source of energy dependent on weather / intermittent supply B1 5(b)(ii) any two from: renewable source of energy no atmospheric pollution conserves fossil fuels owtte do not contribute to global warming B2

This question in 0625/32 Feb/March 2020

11 A model train uses an electric motor. The motor has a coil of wire in a magnetic field. (a) Fig. 11.1 shows a coil of wire in a magnetic field. north pole south pole N S current coil of wire Fig. 11.1 Describe two ways of increasing the turning effect on the coil. … … [2] (b) The motor for the model train uses an alternating voltage of 12 V. This is supplied by the secondary coil of a transformer. The primary coil of the transformer is connected to a mains voltage of 240 V. The primary coil has 900 turns. Calculate the number of turns on the secondary coil. number of turns on the secondary coil = … [3] [Total: 5]

5 marks

Mark scheme: 11(a) any two from: increase current increase magnetic field strength field more turns on coil B2 11(b) (Vp / Vs) = (Np / Ns) in any form C1 Ns = (12 ÷ 240) × 900 C1 45 A1

This question in 0625/32 May/June 2020

12 (a) Fig. 12.1 shows two circuits, A and B, linked by a relay. relay heater switch S relay + switch R 6 V - relay coil 120 V a.c. circuit A circuit B Fig. 12.1 Describe what happens in the two circuits when switch S is closed. … … … … … [3] (b) Another circuit includes a transformer. The input voltage of the transformer is 120 V a.c. The input coil has 480 turns of wire and the output coil has 60 turns of wire. Calculate the output voltage of the transformer. output voltage = … V [3] [Total: 6]

6 marks

Mark scheme: 12(a) any three from: current in relay coil produces magnetic field relay / switch R is closed heater connected to 120 V or switches on B3 12(b) Vs / Vp = Ns / Np in any form C1 (Vs =) (60 × 120) ÷ 480 OR 120 ÷ 8 C1 15 (V) A1

This question in 0625/31 Oct/Nov 2020

11 Fig. 11.1 represents a transformer. The primary coil has 300 turns and the secondary coil has 30 turns. The input voltage is 230 V a.c. primary coil core secondary coil 300 turns 30 turns 230 V Fig. 11.1 (a) Calculate the voltage across the secondary coil. voltage = … V [3] (b) State a suitable material for the core of the transformer. … [1] (c) Some transformers produce high electrical voltage for the transmission of electrical energy. Describe two advantages of high-voltage transmission. 1. … … 2. … … [2] [Total: 6]

6 marks

Mark scheme: 11(a) Vp ÷ Vs = Np ÷ Ns C1 230 ÷ Vs = 300 ÷ 30 C1 23 (V) A1 11(b) (soft) iron B1 11(c) Any two from: less energy or power wasted OR less heating(of wires) OR more efficient lower current (in transmission wires) can use thinner (transmission) wires / cables fewer power stations needed (so) lower cost for cable and supporting pylons transmit (energy over) longer distances (without drop in power) B2

This question in 0625/32 Oct/Nov 2020

9 (a) A clamp and stand hold a soft-iron bar above a bench. A coil of wire is wrapped round the soft-iron bar. The coil of wire is part of an electric circuit. Fig. 9.1 shows the arrangement. soft-iron bar S clamp and soft-iron stand disc bench Fig. 9.1 Switch S is closed. A student holds a soft-iron disc close to the bar and releases the disc. The disc becomes attached to the bar as shown in Fig. 9.1. Explain why the soft-iron disc is attracted to the soft-iron bar. … … … [3] (b) The circuit in Fig. 9.1 is used to operate a bell in a different circuit, as shown in Fig. 9.2. soft-iron bar S clamp soft-iron arm and stand contacts pivot bell insulator Fig. 9.2 (i) Switch S is closed. The soft-iron arm is attracted to the soft-iron bar. Explain why the bell operates when the switch S is opened. … … … … … [4] (ii) The switch S is closed. The soft-iron arm is attracted to the soft-iron bar. The battery in the circuit containing the soft-iron bar becomes fully discharged. State and explain whether the bell operates. … … [1] [Total: 8]

8 marks

Mark scheme: 9(a) current (in coil / circuit) B1 magnetic (effect of current) C1 coil OR soft iron rod / bar (becomes a electro)magnet A1 9(b)(i) any four from: residual magnetism circuit broken OR no current in electromagnet / circuit electromagnet switched off / no longer attracts the (pivoted) arm (pivoted) arm falls current in bell OR alarm / bell circuit complete B4 9(b)(ii) bell rings M0 (because) electromagnet switched off / no longer attracts the (pivoted) arm / (pivoted) arm falls B1

This question in 0625/33 Oct/Nov 2020

10 (a) Describe an experiment to show that a force acts on a current-carrying conductor placed in a magnetic field. You may draw a diagram to help your answer. … … … … … … … [4] (b) A current in a wire can cause the wire to get hot and melt the wire. Describe how to reduce the heating effect of a current. … … [1] [Total: 5]

5 marks

Mark scheme: 10(a) wire or rod positioned between magnetic poles B1 diagram or description of working circuit B1 current in circuit OR switch circuit on B1 wire / rod moves owtte B1 10(b) use resistor in series / only allow current to flow for a short time / use a smaller current / use a smaller p.d. / reduce the pd of the power supply B1

This question in 0625/33 Oct/Nov 2020

8 (a) Fig. 8.1 shows the magnetic field pattern around a bar magnet. S N Fig. 8.1 (i) Describe an experiment to identify the pattern and direction of magnetic field lines around a bar magnet as shown in Fig. 8.1. You may add to Fig. 8.1 as part of your answer. … … … … … [3] (ii) State a material that can be used to make a permanent bar magnet. … [1] (b) A student uses two bar magnets to create a uniform magnetic field. He places a current- carrying wire at right angles to the magnetic field, as shown in Fig. 8.2. separation of poles bar magnet bar magnet N S uniform current-carrying magnetic field wire Fig. 8.2 There is a force on the current-carrying wire. (i) The student wants to reverse the direction of the force on the wire. State one change that reverses the direction of the force on the wire. … [1] (ii) The student increases the separation of the poles of the permanent magnets. State and explain how increasing the separation affects the force on the current-carrying wire. … … [2] [Total: 7]

7 marks

Mark scheme: 8(a)(i) (plotting) compass OR iron filings B1 detail of method B1 use of (plotting) compass to give direction of field B1 8(a)(ii) steel B1 8(b)(i) reverse magnetic field owtte OR reverse current in wire B1 8(b)(ii) force is weaker B1 (because) magnetic field is weaker B1

This question in 0625/32 Feb/March 2021

10 A student uses a laptop computer. The student notices that the cable connecting the power adapter for a laptop to the mains electricity supply is damaged as shown in Fig. 10.1. Fig. 10.1 (a) State the hazard of using mains equipment with damaged insulation. … [1] (b) Describe how a fuse protects a mains electrical appliance. … … … [3] (c) The laptop computer uses a transformer to change the voltage of the mains electricity supply. The input (primary) voltage is 120 V. The input (primary) coil has 2000 turns and the output (secondary) coil has 200 turns. Calculate the output (secondary) voltage from the transformer. output (secondary) voltage = … V [3] (d) State the name of the material used in the core of the transformer. … [1] [Total: 8]

8 marks

Mark scheme: 10(a) electrocution OR overheating / fire B1 10(b) large current (in fuse) B1 (causes) fuse / it to melt B1 isolating appliance from supply OR prevents current in appliance OR breaks circuit B1 10(c) Vs / Vp = Ns / Np C1 Vs / 120 = 200 / 2000 OR Vs = 120 × 200 / 2000 OR Vs = 120 / 10 C1 12 (V) A1 10(d) (soft) iron B1

This question in 0625/32 Feb/March 2021

11 A student uses a coil and a magnet on a spring to generate an electromotive force (e.m.f.) that varies. He suspends the magnet above a coil as shown in Fig. 11.1. spring N magnet S to centre-reading coil voltmeter X Fig. 11.1 (a) The student pulls the magnet through the coil to X and then releases it. The magnet moves up and down through the coil. State the type of voltage induced in the coil. Tick (3) one box. alternating digital direct [1] (b) State two ways of increasing the voltage induced in the coil. 1. … 2. … [2] [Total: 3]

3 marks

Mark scheme: 11(a) top box ticked (alternating) B1 11(b) any two from: increase strength of magnet/magnetic field increase speed of magnet increase number of turns (of wire in coil) B2

This question in 0625/31 May/June 2021

10 Fig. 10.1 shows an electric screwdriver which has an electric motor and a battery. electric motor battery Fig. 10.1 (a) (i) The electric motor has a current-carrying coil in a magnetic field. The screwdriver’s manufacturer decides that the turning effect of the coil is too small. State three ways of increasing the turning effect of the coil. 1. … 2. … 3. … [3] (ii) The coil in the motor can rotate in either direction. State what happens in the coil to reverse the direction of rotation. … [1] (b) The battery is charged using a transformer connected to an a.c. power supply. The primary voltage Vp to the transformer is 234 V and the secondary voltage Vs of the transformer is 18 V. The number of turns on the primary coil Np is 2470 turns. Calculate the number of turns on the secondary coil Ns. Ns = … [3] [Total: 7]

7 marks

Mark scheme: 10(a)(i) increase current (in coil) B1 increase strength of magnet(s) or magnetic field(s) B1 increase the number of turns on the coil B1 Question Answer Marks 10(a)(ii) (direction of the) current (in the coil) is reversed B1 10(b) (Vp/Vs) = (Np/Ns) in any form C1 234 ÷ 18 = 2470 ÷ Ns OR Ns = 2470 ÷ (234 ÷ 18) OR 2470 ÷ 13 C1 (turns on secondary/output coil Ns =) 190 A1

This question in 0625/32 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

11 (a) Fig. 11.1 shows a magnet and a coil of wire connected to a galvanometer. magnet coil of wire S N direction of movement galvanometer Fig. 11.1 A student slowly moves the magnet into the coil. The pointer on the galvanometer moves to the left. This deflection shows that an electromotive force (e.m.f.) is induced in the coil. State three ways of increasing the size of the e.m.f. in the coil. 1 … 2 … 3 … [3] (b) Fig. 11.2 shows a transformer. primary coil secondary coil 1000 turns 50 turns 240 V core Fig. 11.2 (i) Name one material that is suitable for the core of the transformer. … [1] (ii) The primary coil has 1000 turns and its input is 240 V a.c. The secondary coil has 50 turns. Calculate the output voltage across the secondary coil. output voltage = … V [3] [Total: 7]

7 marks

Mark scheme: 11(a) strong(er) magnet B1 move (magnet) more quickly / faster movement B1 more turns / coils (per unit length) B1 11(b)(i) (soft) iron B1 11(b)(ii) Vp / Vs = Np / Ns in any form C1 (Vs =) 240 × 50 / 1000 C1 12 (V) A1

This question in 0625/32 Oct/Nov 2021

10 (a) Fig. 10.1 shows the arrangement for transferring electrical energy from a power station to homes and factories. factories cables homes power station step-up step-down transformer transformer Fig. 10.1 Explain why the arrangement includes a step-up transformer and a step-down transformer. … … … … … [4] (b) A transformer has 2000 turns on the primary coil and 500 turns on the secondary coil. The potential difference (p.d.) across the primary coil is 240 V a.c. Calculate the p.d. across the secondary coil. p.d. across the secondary coil = … V [3] [Total: 7]

7 marks

Mark scheme: 10(a) any four from: step up: increase voltage / high voltage in power lines lower current reduce power / energy losses step down: lower voltage / low voltage in homes safety/match for appliances / machines thinner cables (can be used) 10(b) Vp / Vs = Np / Ns in any form C1 Vs = (500 / 2000) × 240 C1 60 (V) A1

This question in 0625/33 Oct/Nov 2021

11 A battery charger for a laptop computer includes a transformer. (a) The primary voltage Vp to the transformer is 240 V. The number of turns on the primary coil Np is 590 turns and the number of turns on the secondary coil Ns of the transformer is 48 turns. Calculate the secondary voltage Vs of the transformer. secondary voltage Vs = … V [3] (b) The plug connecting the transformer to the supply voltage contains a fuse. Describe how a fuse works. … … … … [3] [Total: 6]

6 marks

Mark scheme: 11(a) 20 (V) A3 Vs / 240 = 48 / 590 OR Vs = (48 / 590) × 240 OR Vs = 240 ÷ 12.3 OR 48 / 590 = ? / 240 OR 240 48 590 × (C2) Vs / Vp = Ns / Np in any form (C1) 11(b) large current (in fuse) B1 (causes) fuse to melt B1 isolating appliance from supply OR prevents / stops current in appliance / circuit B1

This question in 0625/32 Feb/March 2022

5 (a) Describe how a wind turbine generates electricity from energy in the wind. … … … [3] (b) Apart from cost, state two advantages of generating electricity using wind turbines compared with using a power station that burns coal. 1. … 2. … [2] (c) Apart from cost, state two disadvantages of generating electricity using wind turbines compared with using a power station that burns coal. 1. … 2. … [2] [Total: 7]

7 marks

Mark scheme: 5(a) any three from: (moving) air has kinetic energy OR wind has kinetic energy (moving) air / wind turns turbine/blades turbine turns generator (rotating) generator produces/generates electricity B3 5(b) any two from: (wind is) renewable (energy source) no greenhouse gases / CO2 produced (during operation) no SO2 OR acidic gases produced (during operation) OR no nitrous oxides produced B2 5(c) any two from: large(r) area of land needed OR dilute energy source intermittent/inconsistent/unreliable supply OR cannot work if wind too strong/weak (possible) harm to (migrating) birds difficult to maintain (particularly if off-shore) B2

This question in 0625/31 May/June 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

10 A microwave oven has a metal case and is connected to a 240 V electricity supply. (a) The microwave oven is fitted with a 13 A fuse and an earth wire is connected to the metal case of the microwave oven. A fault occurs and the live wire of the microwave oven touches the metal case. Explain how the fuse and an earthed metal case protect the appliance and the user. … … … … … [4] (b) The electric circuit for the microwave oven includes a transformer. The voltage to the primary coil of the transformer Vp is 240 V. The number of turns on the primary coil Np is 70. The number of turns on the secondary coil Ns is 560. Calculate the secondary voltage Vs for the transformer. Vs = … V [3] [Total: 7]

7 marks

Mark scheme: 10(a) any four from: Earth wire keeps case at zero volts/earth (potential) (so) user not electrocuted (live wire touching metal case produces) large current (in fuse/earth wire) (causes) fuse to melt isolating appliance from supply OR (so) no current in appliance OR disconnects/breaks the circuit prevent(s/ing electrical) fire/overheating (in cables/appliance) Question Answer Marks 10(b) 1920 (V) A3 Vs / 240 = 560/70 OR Vs = (560/70)  240 OR Vs = 240  8 OR 560/70 = ? / 240 (C2) Vs/Vp = Ns/Np in any form (C1)

This question in 0625/31 May/June 2022

4 Fig. 4.1 shows parts of a coal-fired power station. transformer transmission lines X Y coal steam boiler cold water Fig. 4.1 (a) (i) State the names of the parts of the power station labelled X and Y. X … Y … [2] (ii) Describe two useful energy transfers in this power station. 1. … 2. … [2] (b) The power station contains a transformer. The primary voltage Vp for the transformer is 25 000 V. The number of turns on the primary coil Np is 600. The number of turns on the secondary coil Ns is 4800. Calculate the secondary voltage Vs for the transformer. Vs = … V [3] (c) Give two reasons for transmitting electrical energy at very high voltages. 1. … … 2. … … [2] [Total: 9]

9 marks

Mark scheme: 4(a)(i) (X is a) turbine B1 (Y is a) generator B1 4(a)(ii) any two from: chemical energy (in coal) to thermal/internal energy (in boiler) thermal/internal energy (of steam/water) to kinetic energy (of steam) kinetic energy of steam to kinetic energy of turbine/generator kinetic energy (of generator) to electrical energy B2 4(b) 200 000 (V) A3 Vs / 25 000 = 4800/600 OR Vs = (4800/600)  25 000 OR Vs = 25 000  8 OR 4800/600 = ? / 25 000 (C2) Vs/Vp = Ns/Np in any form (C1) Question Answer Marks 4(c) any two from: reduces current (in cables) less energy or power wasted or less heating or more efficient enables use of thinner cables (so) lower cost for cable and supporting pylons transmit (electricity over) longer distances (without drop in p.d.) B2

This question in 0625/32 May/June 2022

10 (a) Fig. 10.1 shows a wire passing through a card. There is a large electric current in the wire in the direction shown. Fig. 10.2 shows the same arrangement when viewed from above the card. card large current card Fig. 10.1 Fig. 10.2 There is a pattern of magnetic field lines around the wire due to the current in the wire. On Fig. 10.2, draw the pattern and direction of the magnetic field as if viewed from above the card. [3] (b) Fig. 10.3 shows a wire XY carrying a large electric current between the poles of a permanent magnet. There is an upward force on the wire XY. X current force magnet magnet N S Y Fig. 10.3 (i) State two different ways of increasing the force due to the current in the wire XY. … … [2] (ii) State two different ways of making the force on the wire XY act downwards. … … [2] [Total: 7]

7 marks

Mark scheme: 10(a) circles drawn B1 concentric (by eye) with wire B1 arrow drawn clockwise on/near field (line) B1 10(b)(i) any two from: increase current (in wire) increase strength of magnets or magnetic field move poles closer together B2 10(b)(ii) reverse the (direction of the) current (in the wire) B1 reverse the magnetic field B1

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 Fig. 9.1 shows a transformer used on a building site. output socket mains plug for transformer Fig. 9.1 (a) The mains plug for the transformer contains a fuse. (i) Give a reason why the plug includes a fuse. … [1] (ii) Explain how a fuse works. … … [2] (b) The mains input (primary) potential difference (p.d.) to the transformer is 230 V a.c. The number of turns on the input (primary) coil is 314. The number of turns on the output (secondary) coil is 150. Calculate the output (secondary) p.d. from the transformer. output p.d. = … V [3] (c) Fig. 9.2 shows an outline of the transformer. core primary coil secondary coil 314 turns 150 turns 230 V a.c. Fig. 9.2 (i) State a suitable material for the core of the transformer. … [1] (ii) State a suitable material for the primary and secondary coils of the transformer. … [1] (iii) Explain how Fig. 9.2 shows a step-down transformer. … [1] [Total: 9]

9 marks

Mark scheme: 9(a)(i) protects (transformer / wiring) from fire / overheating B1 9(a)(ii) any two from: B2 • large current (in fuse) • (causes) fuse to melt • (and so) prevents current in appliance OR breaks circuit OR isolates appliance from supply. 9(b) 110 (V) A3 Vs / 230 = 150 / 314 OR Vs = (150 / 314) × 230 OR Vs = 230 / 2.093 OR 150 / 314 = ? / 230 C2 Vs / Vp = Ns / Np C1 9(c)(i) (soft) iron B1 9(c)(ii) copper B1 9(c)(iii) fewer turns on output / secondary (than on input coil) B1

This question in 0625/31 Oct/Nov 2022

9 Fig. 9.1 shows a transformer. An a.c. voltmeter is connected to the output of the secondary coil. core 10 V a.c. V voltmeter number of number of primary turns = 200 secondary turns = 800 Fig. 9.1 (a) State the meaning of a.c. … [1] (b) State the name of the type of transformer shown. … [1] (c) State a suitable material for the core of the transformer in Fig. 9.1. … [1] (d) Using the information in Fig. 9.1, calculate the reading on the voltmeter. reading on voltmeter = … V [3] (e) The 10 V a.c. power supply is replaced by a 10 V d.c. battery. State the reading on the voltmeter. reading on voltmeter = … V [1] [Total: 7]

7 marks

Mark scheme: 9(a) alternating (current) B1 9(b) step-up B1 9(c) (soft) iron B1 9(d) 40 (V) A3 (VS =) 800 / 200  10 (C2) VP / VS = NP / NS in any form (C1) 9(e) zero B1

This question in 0625/32 Oct/Nov 2022

10 (a) Fig. 10.1 shows the equipment used by a teacher in a laboratory demonstration. thin string metal wire magnet battery S N direction of movement wooden clamp switch and stand Fig. 10.1 The teacher closes the switch and there is a current in the metal wire. A force acts on the wire. The wire moves in the direction shown in Fig. 10.1. (i) State two changes that increase the force on the wire. 1. … [1] 2. … [1] (ii) State one change that reverses the direction of the force on the wire. … [1] (b) Fig. 10.2 shows the poles of the magnet. Draw the shape and show the direction of the magnetic field in the gap between the poles of the magnet. N S Fig. 10.2 [2] [Total: 5]

5 marks

Mark scheme: 10(a)(i) 1 increase the current / pd / emf / voltage (of cell) B1 2 stronger magnet B1 10(a)(ii) reverse battery OR reverse current (direction) OR reverse magnetic field owtte B1 10(b) 3 or more correct lines B1 direction from N to S indicated B1

This question in 0625/32 Oct/Nov 2022

10 (a) Fig. 10.1 shows two coils of wire P and Q, each in a circuit. The ends of the coils are close but not touching. S G P Q Fig. 10.1 Now, switch S is closed. The pointer in the sensitive ammeter G deflects and then returns to its zero position. Explain why the pointer in sensitive ammeter G deflects. … … … [3] (b) Describe the construction of a step-up transformer. You may draw a labelled diagram as part of your answer. … … … [3] [Total: 6]

6 marks

Mark scheme: 10(a) any three from B3 (when switch S closed) current in coil P coil P has (changing) magnetic field magnetic field (from P) links with / cuts coil Q e.m.f. / voltage / current induced / produced / generated in coil Q 10(b) two coils (of copper wire) B1 (wrapped around / linked by soft) iron core B1 more turns on secondary coil OR less turns on primary coil B1

This question in 0625/32 Feb/March 2023

10 (a) Fig. 10.1 shows an arrangement used to demonstrate electromagnetic induction. magnet moves towards coil coil of wire S N permanent magnet sensitive voltmeter Fig. 10.1 (i) When the magnet moves towards the coil of wire, the pointer on the sensitive voltmeter deflects to the right. Explain why the pointer deflects. … … [2] (ii) State two changes that increase the deflection on the sensitive voltmeter. 1 … 2 … [2] (b) Fig. 10.2 shows the symbol for a transformer. The primary coil is connected to a voltage of 180 V a.c. primary voltage Vp = 180 V a.c. primary coil secondary coil 4800 turns 200 turns secondary voltage Vs Fig. 10.2 Calculate the secondary voltage Vs for the transformer. Vs = … V [3] [Total: 7]

7 marks

Mark scheme: 10(a)(i) any two from:  magnetic field  cuts / links with coil / conductor / wire  e.m.f. / voltage / p.d. induced (in coil) 10(a)(ii) any two from:  increase strength of the magnet(ic field)  increase speed of the magnet  increase (the number of) turns on coil B2 10(b) (Vs =) 7.5 (V) A3 Vs/ 180 = 200 / 4800 OR (Vs =) (200  180)  4800 (C2) Vs/ Vp = Ns/ Np (C1)

This question in 0625/31 May/June 2023

9 A student has a desktop computer that connects to the 240 V a.c. mains electrical supply. Fig. 9.1 shows the desktop computer. desktop computer Fig. 9.1 (a) The desktop computer has an on-off switch in one of the wires that connect it to the mains supply. State and explain which wire includes the switch. … … … [3] (b) The desktop computer uses a transformer to change the 240 V a.c. voltage to a 12 V a.c. voltage. (i) State the name of this type of transformer. … [1] (ii) Describe the construction of this transformer. You may include a labelled diagram. … … … … [4] [Total: 8]

8 marks

Mark scheme: 9(a) (switch is in) the live wire B1 (so when switch is off, desktop is) disconnected from supply / mains(voltage) OR high voltage B1 (so) no current (in computer / circuit) OR no risk of electrocution B1 9(b)(i) step-down (transformer) B1 9(b)(ii) any four from:  (soft) iron core  two coils of copper wire  primary coil AND secondary coil  transformer equation stated  turns ratio of 20 : 1 OR 240 : 12 owtte OR use of transformer equation B4

This question in 0625/32 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

8 Fig. 8.1 shows a solenoid (long coil of wire) connected in a circuit. When the switch is closed, there is a large current in the circuit. solenoid Fig. 8.1 (a) Describe an experiment to identify the pattern and direction of the magnetic field around the solenoid. You may draw on Fig. 8.1 as part of your description. … … … [3] (b) A solenoid P is placed close to another solenoid Q. Solenoid Q is connected to a sensitive voltmeter. The arrangement is shown in Fig. 8.2. switch pointer sensitive voltmeter P Q Fig. 8.2 Describe and explain what happens when the switch is closed. … … … … [4] [Total: 7]

7 marks

Mark scheme: 8(a) (plotting) compass OR iron filings B1 detail of method B1 idea of using a (plotting) compass to give direction of magnetic field B1 8(b) any four from: B4 current in coil P (changing) magnetic field around / in coil P (magnetic field) links with / cuts coil Q an induced emf (across) coil Q OR voltage / current produced / generated in coil Q (induced emf) causes pointer on (sensitive) voltmeter to move when current steady no changing magnetic field OR no field (lines) cutting coil Q pointer then returns to zero

This question in 0625/31 Oct/Nov 2023

10 (a) Different materials have differing magnetic properties. (i) State the name of a material that is suitable for a temporary magnet. … [1] (ii) State the name of a material that is suitable for a permanent magnet. … [1] (iii) State how a magnet can show that a material is non‑magnetic. … [1] (b) A teacher uses the arrangement in Fig. 10.1 to demonstrate an electric bell. When the switch is closed, the hammer repeatedly hits the metal gong. springy iron metal contact strip plastic holder metal hammer switch coil of wire battery metal gong iron nail Fig. 10.1 Using the information in Fig. 10.1, explain why the hammer repeatedly hits the metal gong when the switch is closed. … … … … … [4] [Total: 7]

7 marks

Mark scheme: 10(a)(i) (soft) iron B1 10(a)(ii) steel B1 10(a)(iii) magnet does not attract a non-magnetic material B1 10(b) any four from: B4 (when switch closed) there is a complete circuit current in the circuit magnetic effect (of current / in coil) owtte (coil and nail become) electromagnet (springy) iron (strip) attracted to (nail / electromagnet) circuit broken owtte springy iron strip springs back / makes contact (again) owtte

This question in 0625/32 Oct/Nov 2023

8 (a) Fig. 8.1 shows an arrangement for transmitting electricity generated by a power station. power cables 360 kV a.c. power station generating electricity at 25 kV a.c. homes step-up step-down transformer transformer Fig. 8.1 (not to scale) The step-up transformer has 500 turns on the primary coil. Calculate the number of turns on the secondary coil of the step-up transformer. Use the information given in Fig. 8.1. number of secondary turns = … [3] (b) State two benefits of using high voltages for transmitting electricity. 1 … 2 … [2] [Total: 5]

5 marks

Mark scheme: 8(a) 7200 A3 (Ns =) 500  360 / 25 OR 360  20 (C2) Vp / Vs = Np / Ns (C1) 8(b) any two from: B2 smaller current (in cables) more efficient less power / heating losses thinner / cheaper cables / pylons further apart owtte less voltage drop OR transfer energy over longer distance

This question in 0625/33 Oct/Nov 2023

9 (a) Describe what is meant by alternating current (a.c.). … [1] (b) A teacher demonstrates how a loudspeaker works by using the equipment shown in Fig. 9.1. direction of vibration of paper cone strong magnet N S coil paper cone Fig. 9.1 There is an alternating current in the coil. The paper cone and coil vibrate as shown in Fig. 9.1. (i) Explain why the paper cone vibrates. Use your ideas about magnetism. … … … … [3] (ii) When the paper cone vibrates, the teacher hears a sound. Suggest a value for the frequency of the alternating current. Include the unit. frequency = … unit … [2] [Total: 6]

6 marks

Mark scheme: 9(a) (current repeatedly) changes direction B1 9(b)(i) any three from: B3 magnetic effect of current coil becomes an electromagnet attracted to magnet repelled by magnet 9(b)(ii) any number(s) between 20 and 20 000 B1 Hz / kHz B1

This question in 0625/33 Oct/Nov 2023

9 (a) Fig. 9.1 shows the power cable for connecting a desktop computer to the mains electricity circuit. power cable Fig. 9.1 (i) State the name of each of the three wires inside the power cable. 1 … 2 … 3 … [2] (ii) The cable is designed for a maximum current of 13 A. Suggest one hazard due to a current of 30 A in the cable. … [1] (b) There is a transformer in the desktop computer. The input voltage to the primary coil Vp is 230 V (a.c.). The number of turns on the primary coil Np is 720. The number of turns on the secondary coil Ns is 50. (i) Calculate the output voltage Vs of the secondary coil. secondary coil output voltage Vs = … V [3] (ii) The current in the input coil of the transformer is 1.4 A. Calculate the input power to the desktop computer. input power = … W [3] [Total: 9]

9 marks

Mark scheme: 9(a)(i) live (wire) neutral (wire) earth (wire) 3 correct – 2 marks 1 or 2 correct – 1 mark B2 9(a)(ii) idea of (cable) overheating OR (insulation) melting / burning B1 9(b)(i) (secondary coil voltage Vs =) 16 (V) A3 230 / Vs = 720 / 50 OR (Vs =) {230  50} ÷ 720 (C2) (Vp / Vs) = (Np / Ns) in any form (C1) 9(b)(ii) (P =) 320 (W) A3 (P =) 1.4  230 (C2) (P =) I  V (C1)

This question in 0625/31 May/June 2024

8 (a) The battery in a laptop computer is connected to a battery charger for 20 minutes. The potential difference (p.d.) across the battery is 14 V. The current in the battery is 1.8 A. Calculate the energy transferred to the battery in 20 minutes. energy transferred = … J [4] (b) The battery charger includes a transformer. Fig. 8.1 shows the transformer. core input voltage output voltage = 240 V a.c. = 16 V a.c. primary coil secondary coil Fig. 8.1 (not to scale) (i) State the name of the material used for the core of the transformer. … [1] (ii) The transformer has 4800 turns on the primary (input) coil. Calculate the number of turns on the secondary (output) coil. Use information from Fig. 8.1. number of turns = … [3] [Total: 8]

8 marks

Mark scheme: 8(a) (E =) 30 000 (J) A4 (E =) 1.8  1200  14 OR 2160  14 (C3) (E =) 1.8  20  14 OR 36  14 (C2) (E =) I  t  V OR E = P  t AND P = I  V (C1) conversion 20 (minutes) = 1200 (s) (C1) 8(b)(i) (soft) iron B1 8(b)(ii) 320 (turns) A3 16 / 240 = Ns / 4800 OR 240 / 16 = 4800 / Ns OR Ns = 4800  {16 / 240} (C2) (Vs / Vp) = (Ns / Np) in any form (C1)

This question in 0625/32 May/June 2024

9 (a) Fig. 9.1 shows three devices: a compass, a transformer and an electromagnet. The main parts of the devices are labelled. transformer core compass needle electromagnet core transformer coils Fig. 9.1 Complete Table 9.1 by adding a suitable metal for each part. Choose from the metals in the list. Each metal can be used once, more than once or not at all. aluminium copper soft iron silver steel Table 9.1 part metal compass needle transformer core transformer coils electromagnet core [2] (b) The primary coil of a transformer is connected to a mains supply of 220 V a.c. The primary coil has 1500 turns and the secondary coil has 650 turns. Calculate the output voltage of the secondary coil. output voltage = … V [3] [Total: 5]

5 marks

Mark scheme: 9(a) part metal compass needle steel transformer core soft iron transformer coils copper / silver electromagnet core soft iron 4 correct – 2 marks 2 or 3 correct – 1 mark B2 9(b) 95 (V) A3 (Vs =) 650 / 1500  220 OR 1500 / 650 = 220 / Vs (C2) (Vp / Vs) = (Np / Ns) in any form (C1)

This question in 0625/33 May/June 2024

10 In an experiment, a student uses an electrical heater connected to a power supply. (a) The current in the electrical heater is 2.2 A. The voltage (p.d.) across the heater is 12 V. Calculate the energy transferred to the heater in 90 s. energy transferred = … J [3] (b) The power supply is connected to the electrical mains by a cable that consists of three wires. State the name for each of the three wires in the cable. 1 … 2 … 3 … [2] (c) The power supply includes a transformer. The voltage (Vp) across the primary coil of the transformer is 228 V. The voltage (Vs) across the secondary coil of the transformer is 12 V. The number of turns on the primary coil (Np) is 760. Calculate the number of turns (Ns) on the secondary coil. number of turns on secondary coil = … [3] [Total: 8]

8 marks

Mark scheme: 10(a) (energy =) 2400 (J) A3 (energy =) 2.2  90  12 (C2) (energy =) current  time  voltage OR(E) = V  I  t OR (energy =) power  time OR P  t (C1) 10(b) live OR line earth OR ground neutral B2 10(c) 40 A3 (Ns) = (12  228)  760 OR 228 / 12 = 760 / Ns (C2) Ns / Np = Vs / Vp (C1)

This question in 0625/31 Oct/Nov 2024

9 (a) Fig. 9.1 represents part of a d.c. electric motor. The coil of wire rotates at a steady speed. current coil of wire Fig. 9.1 State two ways to make the coil rotate faster. 1 … 2 … [2] (b) Fig. 9.2 shows an electric fan. Fig. 9.2 The electric motor for the fan requires 120 V a.c. The mains voltage is 220 V a.c. A transformer steps down the mains voltage as shown in Fig. 9.3. primary coil secondary coil 800 turns mains voltage 220 V a.c. output voltage 120 V a.c. Fig. 9.3 Calculate the number of turns on the secondary coil. Use the information in Fig. 9.3. number of turns on the secondary coil = … [3] (c) A plug connects the transformer to the mains supply. There is a fuse in the plug. Describe how a fuse works. … … … [2] [Total: 7]

7 marks

Mark scheme: 9(a) any two from: B2 • increase (battery) voltage OR larger current in coil • increase strength of magnet(ic) field OR strong(er) magnet • increase number of turns (in coil) 9(b) 440 (turns) A3 (NS =) 800  120 / 220 (C2) VP / VS = NP / NS (C1) 9(c) any two from: B2 • large current (in fuse) • (causes) fuse to melt • isolating appliance from supply OR prevents / stops current in appliance

This question in 0625/32 Oct/Nov 2024

9 (a) Fig. 9.1 shows a magnet spinning steadily near to a coil. There is a reading on the voltmeter. coil magnet N S pivot V Fig. 9.1 Explain why there is a reading on the voltmeter. … … … [2] (b) A step-down transformer reduces the mains voltage of 220 V a.c. to 12 V a.c. The transformer has 5000 turns on the primary coil. Calculate the number of turns on the secondary coil. number of turns = … [3] [Total: 5]

5 marks

Mark scheme: 9(a) induced e.m.f.(in the coil) B1 changing magnetic field (in the coil) B1 9(b) (number of turns =) 270 A3 (NS =) 12 / 220  5000 (C2) VP / VS = NP / NS (C1)

This question in 0625/33 Oct/Nov 2024

10 Fig. 10.1 shows the apparatus used by a student to demonstrate electromagnetic induction. permanent S magnet solenoid V voltmeter N Fig. 10.1 (a) Describe how the student uses the apparatus to demonstrate electromagnetic induction. … … … [2] (b) State two separate changes the student must make to the apparatus to increase the electromotive force (e.m.f.) induced in the coil. 1 … 2 … [2] (c) Fig. 10.2 represents a transformer. transformer core primary coil coil X 100 V (40 turns) (80 turns) Fig. 10.2 (i) State a suitable material for the transformer core. … [1] (ii) State the term used to describe coil X in Fig. 10.2. … [1] (iii) State the term used to describe the type of transformer represented in Fig. 10.2. … [1] [Total: 7]

7 marks

Mark scheme: 10(a) move the magnet M1 {into OR out of OR relative to} the solenoid / coil A1 10(b) any two from: B2 use a stronger magnet increase the number of turns on the coil increasing the speed of (movement of the) magnet 10(c)(i) (soft) iron B1 10(c)(ii) secondary (coil) B1 10(c)(iii) step-up (transformer) B1

This question in 0625/32 Feb/March 2025

9 Fig. 9.1 shows a router. The router emits Wi-Fi signals. router Fig. 9.1 (a) The power input to the router circuit is 9.0 W. The potential difference across the router circuit is 12 V. Calculate the current in the router circuit. current in router circuit = … A [3] (b) The energy used by the router each hour is 0.0090 kW h. One unit (kW h) of energy costs 50 cents. Calculate the cost of using the router for 24 hours. cost for 24 hours = … cents [3] (c) The router uses a transformer. The number of turns Np on the primary coil of the transformer is 3600. The primary voltage Vp to the transformer is 240 V. The secondary voltage Vs of the transformer is 12 V. Calculate the number of turns Ns on the secondary coil of the transformer. number of turns on secondary coil = … [3] (d) The mains plug for the router includes a fuse that protects the router. Explain how a fuse works. … … … [3] [Total: 12]

12 marks

Mark scheme: 9(a) (current =) 0.75 (A) A3 (current =) 9 ÷ 12 C2 power = IV OR (I =) P ÷ V C1 9(b) 11 (cents) A3 (cost =) 0.009(0)  24  50 OR 0.216  50 OR 0.009  1200 OR 0.45  24 C2 (cost =) (energy in) kW h  (number of) hours  cost (of one unit) C1 9(c) (Ns =) 180 A3 (Ns =) {12  3600} ÷ 240 OR (Ns =) 3600 ÷ 20 OR 240 ÷ 12 = 3600 ÷ Ns C2 Vs ÷ Vp = Ns ÷ Np C1 9(d) any three from: B3 • idea of large current (in fuse or any part of circuit) • (large current causes) heating in fuse • idea that fuse is made from low melting point wire • fuse / (fuse) wire melts • (and) idea disconnects / isolates (router / wires / circuit) from supply / mains

This question in 0625/31 May/June 2025

8 A television uses many electrical components. (a) The potential difference (voltage) across a component is 72 V. The current in the component is 0.024 A. Calculate the resistance of the component. resistance = … Ω [3] (b) The television uses a transformer. The input voltage (Vp) to the transformer is 120 V. The number of turns (Np) on the input coil is 560. The number of turns (Ns) on the output coil is 70. Calculate the output voltage (Vs) of the transformer. output voltage = … V [3] (c) The potential difference (voltage) across a resistor is 64 V. The current in the resistor is 2.2 mA. Calculate the power of the resistor. power = … W [4] (d) The energy used by the television in one hour is 0.14 kWh. The cost of one kWh of energy is 36 cents. Calculate the cost of using the television for 6.0 hours. cost for 6 hours = … cents [3] [Total: 13]

13 marks

Mark scheme: 8(a) 3000 () A3 72 / 0.024 (C2) V = IR OR (R = )V / I (C1) 8(b) (output voltage Vs =) 15 (V) A3 Vs / 120 = 70 / 560 OR (Vs =) (70 / 560)  120 (C2) Vs / Vp = Ns / Np in any form (C1) 8(c) (power = ) 0.14 (W) A4 (power = ) 2.2  10-3  64 (C3) (power = ) I V (C1) 2.2 (mA) = 0. 0022 (A) OR 2.2 x 10-3 (A) (C1) 8(d) 30 (cents) A3 (cost = ) 0.14  6(.0)  36 OR 0.84  36 OR 0.14  216 OR 5.04  6 (C2) (cost = ) (energy in) kW h  (number of) hours  cost (of one unit) (C1)

This question in 0625/31 Oct/Nov 2025

8 (a) Fig. 8.1 shows a toy train on a railway track with a tunnel. The toy train consists of an engine with a truck that is carrying a magnet. tunnel railway track engine magnet on truck N S Fig. 8.1 Fig. 8.2 shows the toy train approaching the tunnel. lamp direction of movement coil S N track Fig. 8.2 (paper cover of tunnel not shown) The tunnel consists of a coil of wire that is covered in paper. The ends of the coil are connected to a lamp. When the toy train moves through the coil of wire, the lamp becomes bright. (i) Explain why the lamp becomes bright when the toy train moves through the coil of wire. … … … … [2] (ii) Describe two ways of increasing the brightness of the lamp. 1 … [1] 2 … [1] (b) Another toy train uses a transformer. State which metals are used in a transformer. i(i) for the core of a transformer … [1] (ii) for the coils of a transformer … [1] [Total: 6]

6 marks

Mark scheme: 8(a)(i) any two from: B2 1 magnetic field (from magnet) links with / cuts (large) coil 2 relative movement of magnetic field and coil 3 e.m.f. / voltage / current induced / produced / generated (in large coil) 8(a)(ii) any two from: B2 • strong (er) magnet • (train / magnet) move fast (er) owtte • more coils / turns 8(b)(i) (soft) iron B1 8(b)(ii) copper B1

This question in 0625/32 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