Electromagnetic effects — Paper 2 · IGCSE Physics 0625

32 A battery charger plugs into a 230 V a.c. supply. The charger is used to charge a 6.0 V d.c. battery. The charger contains diodes and a transformer. What is the purpose of these components? diodes transformer A rectify the a.c. steps down the voltage B rectify the a.c. steps up the voltage C step down the voltage rectifies the a.c. D step up the voltage rectifies the a.c.

1 marks

Answer: A

This question in 0625/22 Feb/March 2016

35 An electron moves into a uniform magnetic field. The arrow shows the initial direction of motion of the electron. The direction of the magnetic field is into the plane of the page (away from you). uniform magnetic field electron In which direction does a force act on the electron when it enters the magnetic field? A into the page B out of the page C towards the bottom of the page D towards the top of the page

1 marks

Answer: C

This question in 0625/22 Feb/March 2016

36 The diagram shows an a.c. generator. rotation of coil coil N S output voltage As the coil passes through the position shown, the output voltage is +10 V. When does the output voltage become –10 V? A when the coil has turned through 90° B when the coil has turned through 180° C when the coil has turned through 270° D when the coil has turned through 360°

1 marks

Answer: B

This question in 0625/22 Feb/March 2016

34 A strong electromagnet is used to attract pins. core current coil pins What happens when the current in the coil is halved? A No pins are attracted. B Some pins are attracted, but not as many. C The same number of pins is attracted. D More pins are attracted.

1 marks

Answer: B

This question in 0625/21 May/June 2016

35 The diagram shows a transformer. input output voltage voltage primary coil secondary coil 800 turns 40 turns The input voltage is 240 V. What is the output voltage? A 6.0 V B 12 V C 20 V D 40 V

1 marks

Answer: B

This question in 0625/21 May/June 2016

36 The diagram shows a shaded area where the direction of a magnetic field is into the page. A beam of β-particles enters the field as shown. magnetic field into the page beam of β-particles In which direction is the beam of β-particles deflected as they enter the magnetic field? A into the page B out of the page C down the page D up the page

1 marks

Answer: C

This question in 0625/21 May/June 2016

34 A strong electromagnet is used to attract pins. core current coil pins What happens when the current in the coil is halved? A No pins are attracted. B Some pins are attracted, but not as many. C The same number of pins is attracted. D More pins are attracted.

1 marks

Answer: B

This question in 0625/22 May/June 2016

35 The diagram shows a transformer. input output voltage voltage primary coil secondary coil 800 turns 40 turns The input voltage is 240 V. What is the output voltage? A 6.0 V B 12 V C 20 V D 40 V

1 marks

Answer: B

This question in 0625/22 May/June 2016

36 The diagram shows a shaded area where the direction of a magnetic field is into the page. A beam of β-particles enters the field as shown. magnetic field into the page beam of β-particles In which direction is the beam of β-particles deflected as they enter the magnetic field? A into the page B out of the page C down the page D up the page

1 marks

Answer: C

This question in 0625/22 May/June 2016

35 The diagram shows a transformer. input output voltage voltage primary coil secondary coil 800 turns 40 turns The input voltage is 240 V. What is the output voltage? A 6.0 V B 12 V C 20 V D 40 V

1 marks

Answer: B

This question in 0625/23 May/June 2016

36 The diagram shows a shaded area where the direction of a magnetic field is into the page. A beam of β-particles enters the field as shown. magnetic field into the page beam of β-particles In which direction is the beam of β-particles deflected as they enter the magnetic field? A into the page B out of the page C down the page D up the page

1 marks

Answer: C

This question in 0625/23 May/June 2016

36 An electric current can produce a heating effect and a magnetic effect. Which row shows the effect that a relay uses and one application of a relay? effect used by a relay one application of a relay A heating effect allowing a small current to switch on a large current B heating effect changing the voltage of an a.c. supply C magnetic effect allowing a small current to switch on a large current D magnetic effect changing the voltage of an a.c. supply

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2016

36 An electric current can produce a heating effect and a magnetic effect. Which row shows the effect that a relay uses and one application of a relay? effect used by a relay one application of a relay A heating effect allowing a small current to switch on a large current B heating effect changing the voltage of an a.c. supply C magnetic effect allowing a small current to switch on a large current D magnetic effect changing the voltage of an a.c. supply

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2016

38 A β-particle enters a uniform magnetic field directed out of the page. uniform β-particle magnetic field out of the page In which direction is the β-particle deflected by the field? A towards the top of the page B into the page C out of the page D towards the bottom of the page

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2016

36 An electric current can produce a heating effect and a magnetic effect. Which row shows the effect that a relay uses and one application of a relay? effect used by a relay one application of a relay A heating effect allowing a small current to switch on a large current B heating effect changing the voltage of an a.c. supply C magnetic effect allowing a small current to switch on a large current D magnetic effect changing the voltage of an a.c. supply

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2016

38 An α-particle enters a uniform magnetic field directed out of the page. uniform magnetic field out of the page α-particle In which direction is the α-particle deflected by the field? A into the page B out of the page C to the left D to the right

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2016

35 The diagram shows a simple transformer with an input of 240 V and an output of 40 V. There are 600 turns on the primary coil. primary coil secondary coil 600 input 240 V 40 V output turns How many turns are there on the secondary coil? A 100 B 320 C 400 D 3600

1 marks

Answer: A

This question in 0625/22 Feb/March 2017

36 The diagram shows a current-carrying wire. The wire is at 90° to a magnetic field. The direction of the magnetic field is into the page. magnetic field current into the page wire A force acts on the wire due to the current and the magnetic field. In which direction does the force act? A into the page B out of the page C towards the bottom of the diagram D towards the top of the diagram

1 marks

Answer: D

This question in 0625/22 Feb/March 2017

26 A magnet near a coil of wire is attracted to the coil only when there is a current in the coil. Which statement explains this force of attraction? A The coil of wire has its own gravitational field. B The coil of wire is made from soft iron. C The current in the coil of wire creates a magnetic field. D The current in the coil of wire induces a charge on the magnet.

1 marks

Answer: C

This question in 0625/21 May/June 2017

35 A simple d.c. electric motor is fitted with a coil that rotates in a magnetic field. A commutator connects the power supply to the coil. What is the purpose of the commutator? A It converts a.c. into d.c. in the coil. B It prevents the current from becoming too great, because the coil has a low resistance. C It reverses the direction of the current in the coil after every 180° rotation of the coil. D It switches the current off momentarily after every 90° rotation of the coil.

1 marks

Answer: C

This question in 0625/21 May/June 2017

36 What is the purpose of a relay? A to change a large voltage into a small voltage B to change a small voltage into a large voltage C to use a large current to switch on a small current D to use a small current to switch on a large current

1 marks

Answer: D

This question in 0625/21 May/June 2017

25 A magnet near a coil of wire is attracted to the coil only when there is a current in the coil. Which statement explains this force of attraction? A The coil of wire has its own gravitational field. B The coil of wire is made from soft iron. C The current in the coil of wire creates a magnetic field. D The current in the coil of wire induces a charge on the magnet.

1 marks

Answer: C

This question in 0625/22 May/June 2017

35 What is the purpose of a relay? A to change a large voltage into a small voltage B to change a small voltage into a large voltage C to use a large current to switch on a small current D to use a small current to switch on a large current

1 marks

Answer: D

This question in 0625/22 May/June 2017

36 Which device uses a split-ring commutator? A a d.c. motor B a relay C a transformer D an a.c. generator

1 marks

Answer: A

This question in 0625/22 May/June 2017

24 In which way are a bar magnet and an electromagnet similar? A A bar magnet and an electromagnet are always magnetised when stored. B A bar magnet and an electromagnet can both be used to separate magnetic and non-magnetic materials. C A bar magnet can be made of steel and an electromagnet uses a steel core. D The magnetic field strength of a bar magnet and of an electromagnet can both be varied.

1 marks

Answer: B

This question in 0625/23 May/June 2017

25 A magnet near a coil of wire is attracted to the coil only when there is a current in the coil. Which statement explains this force of attraction? A The coil of wire has its own gravitational field. B The coil of wire is made from soft iron. C The current in the coil of wire creates a magnetic field. D The current in the coil of wire induces a charge on the magnet.

1 marks

Answer: C

This question in 0625/23 May/June 2017

26 A steel magnet is placed in a coil and demagnetised. Which type of current is established in the coil, and how is the current changed? A a direct current in the coil, then reduce the current quickly to zero B a direct current in the coil, then reduce the current slowly to zero C an alternating current in the coil, then reduce the current quickly to zero D an alternating current in the coil, then reduce the current slowly to zero

1 marks

Answer: D

This question in 0625/23 May/June 2017

35 In which device is a split-ring commutator used, and what is its purpose? device purpose A a.c. generator to change the direction of the current in the coil as it turns B a.c. generator to change the output current from d.c. into a.c. C d.c. motor to change the direction of the current in the coil as it turns D d.c. motor to change the input current from a.c. into d.c.

1 marks

Answer: C

This question in 0625/23 May/June 2017

36 What is the purpose of a relay? A to change a large voltage into a small voltage B to change a small voltage into a large voltage C to use a large current to switch on a small current D to use a small current to switch on a large current

1 marks

Answer: D

This question in 0625/23 May/June 2017

36 The diagram shows a copper wire XY connected to a resistor. The wire is moved in the magnetic field between the poles of a magnet. There is an induced current in the wire from X to Y. In which labelled direction is the wire moving? X B A C C N S D Y

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2017

37 The graph shows how the voltage induced across a coil changes with time as the coil spins in a magnetic field. voltage 0 0 time Which graph shows what happens when the coil spins more quickly? (All graphs are drawn to the same scale.) A B voltage voltage 0 0 0 time 0 time C D voltage voltage 0 0 0 time 0 time

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2017

36 The diagram shows a wire hanging freely between the poles of a magnet. There is a current in the wire in the direction shown. wire S N current The magnet and current cause a force to act on the wire. In which direction does this force act? A into the page (away from you) B out of the page (toward you) C to the left D to the right

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2017

37 A 100% efficient transformer has 6000 turns on its primary coil and 600 turns on its secondary coil. The output voltage of the transformer is 12 V. A resistor is connected across the secondary coil and dissipates 24 W of power. primary coil secondary coil 6000 turns 600 turns output voltage 12 V power 24 W What is the current in the primary coil of the transformer? A 0.050 A B 0.20 A C 5.0 A D 20 A

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2017

36 The diagram shows a short-circuited copper coil swinging about an axis at right-angles to a strong magnetic field. The motion induces a current in the coil. axis of rotation of coil coil magnetic field direction of swing of coil What is the effect, if any, of this induced current in the coil? A The induced current has no effect on the movement of the coil because copper is non- magnetic. B The induced current produces a magnetic field of constant magnitude in the coil. C The induced current produces forces that assist the change causing it. D The induced current produces forces that oppose the changes causing it.

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2017

37 Diagram 1 shows a magnet being pushed into a coil that is connected to a centre-zero galvanometer. N stationary magnet S N 0 0 0 N S S diagram 1 diagram 2 diagram 3 Which row shows the directions of the pointer when the magnet is as shown in diagrams 2 and 3? diagram 2 diagram 3 A B C D

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2017

34 Which statement about electromagnetic induction is correct? A A strong magnet that is held stationary near a stationary conductor causes a greater effect than a weak magnet. B The effect occurs when a magnet and a conductor are both moved with the same speed and in the same direction. C The effect occurs when a magnet is moved away from a nearby conductor. D The effect only occurs when a magnet is moved towards a conductor.

1 marks

Answer: C

This question in 0625/21 May/June 2018

35 The diagram shows a current-carrying conductor in a magnetic field. Which arrow shows the direction of the force acting on the conductor? A S N D B C

1 marks

Answer: A

This question in 0625/21 May/June 2018

36 Power losses in transmission cables are reduced by increasing the transmission voltage. What is the explanation for this reduction? A The current decreases, reducing thermal energy losses. B The current increases, increasing the flow of charge. C The resistance of the cable increases, reducing the current. D The resistance of the cable decreases.

1 marks

Answer: A

This question in 0625/21 May/June 2018

34 In an a.c. generator, a coil is rotated in a magnetic field and an electromotive force (e.m.f.) is induced in the coil. In which position of the coil does the e.m.f. have the largest value? A B coil coil N S N S C D coil coil N S N S

1 marks

Answer: A

This question in 0625/22 May/June 2018

35 Wire P carries a current directed perpendicularly into the page. A compass is placed at point Q which is close to wire P. The magnetic field at Q due to the current is very much larger than the magnetic field of the Earth. In which direction does the North pole of the compass point? P B C Q A D

1 marks

Answer: A

This question in 0625/22 May/June 2018

36 A transformer has Np turns in the primary coil and Ns turns in the secondary coil. Which row gives the values of Np and Ns for a transformer that steps up a voltage of 1200 V to 36 000 V? Np Ns A 2 000 60 000 B 2 000 600 000 C 60 000 2 000 D 600 000 2 000

1 marks

Answer: A

This question in 0625/22 May/June 2018

34 A wire connected to a resistor is moved in a magnetic field. A current is induced in the direction shown. In which direction is the wire moved? wire A D B B N S R C induced current

1 marks

Answer: C

This question in 0625/23 May/June 2018

35 The diagram shows a transformer. core primary coil secondary coil Which materials are the most suitable for the core and for the coils? core material coil material A copper copper B copper iron C iron copper D iron iron

1 marks

Answer: C

This question in 0625/23 May/June 2018

38 The radiation from a radioactive source passes between two metal plates, and is deflected as shown in the diagram. Between the plates there is a magnetic field directed into the plane of the paper, as indicated by the crosses. × × × × × × × × × × × × × × × × × × × × Only one type of radiation is present. Which situation is possible? A The source emits alpha particles and there is an upwards electric field between the plates. B The source emits alpha particles and there is no electric field between the plates. C The source emits beta particles and there is an upwards electric field between the plates. D The source emits gamma radiation and there is a downwards electric field between the plates.

1 marks

Answer: C

This question in 0625/23 May/June 2018

25 Iron is used for the core of a transformer and steel is used to make a bar magnet. Which statement explains these uses of iron and of steel? A Iron is a magnetic material and steel is a non-magnetic material. B Iron is a permanent magnetic material and steel is a temporary magnetic material. C Iron is a temporary magnetic material and steel is a permanent magnetic material. D Iron is a non-magnetic material and steel is a magnetic material.

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2018

35 There is a current of 3.0 A in a conductor. The current is changed to 6.0 A in the opposite direction. Which effect does this have on the magnetic field around the conductor? A It decreases and it acts in the opposite direction. B It decreases and it acts in the same direction. C It increases and it acts in the opposite direction. D It increases and it acts in the same direction.

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2018

36 A wire is placed in a strong magnetic field. When a current is passed through the wire it moves upwards, as shown. S N movement The current is reversed. In which direction does the wire move? A downwards B towards the north pole C towards the south pole D upwards

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2018

28 A bar magnet is placed inside a current-carrying coil. The diagram shows four different experiments. 1 2 magnet slowly magnet slowly removed removed + – 3 4 current in coil current in coil slowly reduced slowly reduced + – In which experiments is the magnet demagnetised? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2018

35 Electrical power is transmitted at 400 kV and transformed down to 240 V before being delivered to consumers. Which statement is correct? A A 400 kV cable requires less insulation than a 240 V cable. B Birds are subject to a high-voltage shock when resting on a high-voltage cable. C The current in the transmission wires is equal to the current delivered to the consumers. D With a 400 kV transmission system, a smaller proportion of the energy is used to heat the atmosphere than with a 240 V system.

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2018

36 The diagram shows a coil of wire between the poles of a magnet. 20 turns N S + – power supply The coil consists of 20 turns of insulated wire. The coil is connected to a variable resistor and a power supply. How can the turning effect on the coil be increased? A by moving the poles of the magnet closer to the coil B by reducing the number of turns on the coil while keeping the current constant C by increasing the resistance of the variable resistor D by reversing the terminals of the power supply

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2018

27 A bar magnet is placed inside a current-carrying coil. The diagram shows four different experiments. 1 2 magnet slowly magnet slowly removed removed + – 3 4 current in coil current in coil slowly reduced slowly reduced + – In which experiments is the magnet demagnetised? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2018

34 The circuit diagram shows an a.c. power supply connected to two diodes and a resistor. a.c. X power supply Y The graph shows the current from the supply. current 0 0 time Which graph shows the current in diode X? A B current current 0 0 0 time 0 time C D current current 0 0 0 time 0 time

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2018

35 A 100% efficient step-down transformer has primary voltage Vp and primary current Ip. Which row compares the secondary voltage with Vp and the secondary current with Ip? secondary voltage secondary current A greater than Vp greater than Ip B greater than Vp less than Ip C less than Vp greater than Ip D less than Vp less than Ip

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2018

36 There is an electric current in a wire. The wire is placed in a magnetic field. A force acts on the wire due to the current. Which statement is correct? A The magnetic field must be produced by a permanent magnet and not by an electromagnet. B The wire must be made from a magnetic material. C When both the current and the magnetic field are reversed, the direction of the force is unchanged. D When the current is reversed, but not the magnetic field, there will be no force on the wire.

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2018

36 Which statement about the direction of a magnetic field at a point is correct? A It is the direction of the force on a north pole placed at that point. B It is the direction of the force on a south pole placed at that point. C It is the direction of the force on a positive charge placed at that point. D It is the direction of the force on a negative charge placed at that point.

1 marks

Answer: A

This question in 0625/22 Feb/March 2019

37 A current-carrying coil is placed in a magnetic field. view from above coil magnetic field lines Which effect does the coil experience? A a change in shape B a change in weight C a resultant force D a turning effect

1 marks

Answer: D

This question in 0625/22 Feb/March 2019

26 Why is soft iron used for the core of an electromagnet? A Soft iron easily becomes a permanent magnet. B Soft iron is a good electrical conductor. C Soft iron is a poor thermal conductor. D Soft iron loses its magnetism when the current in the coil is switched off.

1 marks

Answer: D

This question in 0625/21 May/June 2019

36 What is the purpose of the commutator in a d.c. electric motor? A to control the speed at which the motor rotates B to reverse the direction of the voltage across the power supply every half-turn C to reverse the direction of the current in the motor coil every half-turn D to reverse the direction of spin of the motor coil every half-turn

1 marks

Answer: C

This question in 0625/21 May/June 2019

37 The diagram shows a wire between two magnetic poles. The wire is connected in a circuit with an ammeter. wire N S A The wire is moved downwards, towards the bottom of the page. A current is induced in the wire. In which direction is the force on the wire caused by this current? A towards the bottom of the page B towards the left of the page C towards the right of the page D towards the top of the page

1 marks

Answer: D

This question in 0625/21 May/June 2019

36 The diagram shows a current-carrying wire placed between two magnetic poles. The current is in the direction shown. wire S N current direction What is the direction of the force on the wire? A towards the bottom of the page B towards the top of the page C towards the left-hand side of the page D towards the right-hand side of the page

1 marks

Answer: A

This question in 0625/22 May/June 2019

37 Diagram 1 shows an a.c. generator. The coil is turning as shown. diagram 1 coil N S Diagram 2 shows the output voltage produced by the generator as the coil turns. Which point on diagram 2 shows the voltage induced when the coil is moving through the position shown in diagram 1? diagram 2 output A voltage B 0 0 C time D

1 marks

Answer: B

This question in 0625/22 May/June 2019

26 A metal bar is placed inside a current-carrying coil, as shown in diagram 1. There is a small current in the coil. The bar holds a few nails, as shown in diagram 2. nails diagram 1 diagram 2 When there is no current in the coil, the nails drop off. Which row is correct? metal from which effect of a larger the bar is made current in the coil A soft iron it makes no difference B soft iron the bar holds more nails C steel it makes no difference D steel the bar holds more nails

1 marks

Answer: B

This question in 0625/23 May/June 2019

37 A conductor carrying a current is placed in a magnetic field. In which direction does the force on the conductor act? current A D B N S C

1 marks

Answer: A

This question in 0625/23 May/June 2019

34 A student investigates the output voltage induced across a coil of wire by a bar magnet. When will the induced voltage have the greatest value? A The student slowly moves the bar magnet into the coil of wire. B The student leaves the bar magnet stationary in the coil of wire. C The student quickly removes the bar magnet from the coil of wire. D The student places the bar magnet at rest outside the coil of wire.

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2019

35 There is a current in a wire. The direction of the current is out of the page. Which diagram shows the magnetic field pattern produced? A B key wire carrying a current out of the page C D

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2019

36 Diagram 1 shows a coil of wire P between the poles of a magnet. The ends of coil P are connected to a battery by slip rings. Diagram 2 shows a coil of wire Q between the poles of a different magnet. The ends of coil Q are connected to a battery by a split-ring commutator. P Q N S N S diagram 1 diagram 2 What happens to coils P and Q? coil P coil Q A continuously turns makes one quarter turn anticlockwise anticlockwise then stops B continuously turns makes one quarter turn clockwise clockwise then stops C makes one quarter turn continuously turns anticlockwise then stops anticlockwise D makes one quarter turn continuously turns clockwise then stops clockwise

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2019

39 The diagram shows β-particles being directed between the poles of a magnet. N β-particles S In which direction will the particles be deflected? A into the page B out of the page C towards the bottom of the page D towards the top of the page

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2019

35 The N-pole of a magnet is moved into a coil of wire connected to a galvanometer. coil S N The needle of the galvanometer moves. Which situation must give a smaller galvanometer reading? A Use a coil with fewer turns and a stronger magnet. B Use a coil with fewer turns and a weaker magnet. C Use a coil with more turns and a stronger magnet. D Use a coil with more turns and a weaker magnet.

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2019

36 A step-down transformer is 100% efficient. It has an input voltage of 240 V a.c. and an output voltage of 60 V a.c. The current in the primary coil is 0.50 A. What is the current in the secondary coil? A 0.13 A B 0.50 A C 2.0 A D 8.0 A

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2019

26 A steel bar is placed in an East-West direction for it to be demagnetised. No other magnet is nearby. Which method is not suitable? A Hammering the bar. B Heating the bar to a very high temperature. C Slowly taking the bar out of a coil that carries an alternating current. D Slowly taking the bar out of a coil that carries a direct current.

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2019

34 A wire XY is connected to a resistor R. The wire is moved in the magnetic field between two magnetic poles. In which direction must the wire be moved so that the induced current is in the direction shown? induced current X A S N C D R B Y

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2019

35 A step-up transformer produces a 60 V a.c. output from a 12 V a.c. input. There are 50 turns on the secondary coil. How many turns are there on the primary coil? A 5 B 10 C 50 D 250

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2019

36 An a.c. generator contains a coil that rotates at a rate of 4500 revolutions per minute. What is the frequency of the alternating current? A 1.25 Hz B 75 Hz C 150 Hz D 4500 Hz

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2019

36 The diagram shows a transformer that has an output voltage of 12 V. primary coil with soft iron core 1000 turns 240 V a.c. 12 V a.c. input output secondary coil How many turns of wire are in the secondary coil? A 12 B 20 C 50 D 20 000

1 marks

Answer: C

This question in 0625/22 Feb/March 2020

37 The diagrams show different particles moving through a magnetic field. Which particle experiences a magnetic force acting up out of the plane of the paper? A B proton electron C D proton electron

1 marks

Answer: C

This question in 0625/22 Feb/March 2020

34 The diagram shows a wire between the poles of a magnet. The wire is perpendicular to the page. N wire LEFT RIGHT S The wire is moved and a current is induced upwards, out of the paper. In which direction is the wire moved? A left to right B right to left C up the page D down the page

1 marks

Answer: B

This question in 0625/21 May/June 2020

35 A 100% efficient transformer converts a 240 V input voltage to a 12 V output voltage. The output power of the transformer can be a maximum of 20 W. The output is connected to two 0.30 A bulbs in parallel. One of the bulbs fails. How does the current in the primary coil change? A It decreases by 0.30 A. B It decreases by 0.015 A. C It increases by 0.15 A. D It remains unchanged.

1 marks

Answer: B

This question in 0625/21 May/June 2020

36 Cables transmit electrical power from the output of the transformer at a power station to the input of the transformer at a substation. cables output input transformer at transformer at power station substation The power at the output of the transformer at the power station is 400 MW. Which situation delivers the most power to the input of the transformer at the substation? potential difference at power station transformer diameter of cables output / kV A 200 large B 200 small C 400 large D 400 small

1 marks

Answer: C

This question in 0625/21 May/June 2020

35 The diagram shows the magnetic field due to a current in a solenoid. Where is the magnetic field the strongest? A D B C

1 marks

Answer: C

This question in 0625/22 May/June 2020

36 A beam of electrons is passed through the magnetic field of a magnet. How must the magnet be positioned to deflect the beam in the direction shown? A B e– e– N S direction S of beam direction N of beam C D e– e– S N direction N of beam direction S of beam

1 marks

Answer: B

This question in 0625/22 May/June 2020

36 The coil of a simple a.c. generator rotates steadily in a uniform magnetic field. The diagram shows the position of the coil at time t = 0. coil N S Which graph shows the output voltage for one revolution of the coil? A B V V 0 0 0 t 0 t C D V V 0 0 0 t 0 t

1 marks

Answer: A

This question in 0625/23 May/June 2020

35 A transformer is needed to convert a supply of 240 V a.c. into 4800 V a.c.. NP NS 240 V a.c. 4800 V a.c. Which pair of coils would be suitable for this transformer? number of turns number of turns on primary coil NP on secondary coil NS A 50 1 000 B 240 48 000 C 480 24 D 2000 100

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2020

36 The diagram shows part of a long current-carrying conductor. At which point is the magnetic field strongest? A C D B

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2020

37 A beam of particles moves through a magnetic field. In which situation do the particles experience a magnetic force? A a beam of -particles moving parallel to the magnetic field lines B a beam of electrons moving parallel to the magnetic field lines C a beam of -particles moving perpendicularly across the magnetic field lines D a beam of neutrons moving perpendicularly across the magnetic field lines

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2020

29 Which diagram represents the strength and direction of the magnetic field around a current-carrying conductor? (The direction of the current is into the page.) A B C D

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2020

34 The diagram shows an a.c. generator used to power a lamp. The coil rotates in a clockwise direction. rotation of coil coil I X Y Which magnetic poles are X and Y? X Y A N pole N pole B N pole S pole C S pole N pole D S pole S pole

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2020

35 A transformer is needed to convert a supply of 240 V a.c. into 4800 V a.c.. NP NS 240 V a.c. 4800 V a.c. Which pair of coils would be suitable for this transformer? number of turns number of turns on primary coil NP on secondary coil NS A 50 1 000 B 240 48 000 C 480 24 D 2000 100

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2020

36 The diagram shows a coil of wire wrapped around a soft-iron rod. The wire is connected to a d.c. power supply as indicated. The apparatus is in a region which is totally shielded from the Earth’s magnetic field. + – soft-iron rod P A small compass needle is placed at point P. In which direction does the N pole of the compass needle point? A towards the bottom of the page B towards the left of the page C towards the right of the page D towards the top of the page

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2020

32 Three statements about a relay are given. 1 A relay has a coil that becomes a temporary magnet when in operation. 2 A large current in a relay coil is used to switch off a smaller current. 3 A small current in a relay coil is used to switch on a larger current. Which statements are correct? A 1 and 2 only B 2 and 3 only C 1 and 3 only D 1, 2 and 3

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2020

34 Graph X shows the output from an a.c. generator. Y p.d. X 0 0 time Which changes can be made so that the generator produces graph Y? A Decrease the magnetic field strength and decrease the speed of rotation only. B Increase the magnetic field strength and decrease the number of coils only. C Increase the number of coils only. D Increase the speed of rotation only.

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2020

35 A transformer is needed to convert a supply of 240 V a.c. into 4800 V a.c.. NP NS 240 V a.c. 4800 V a.c. Which pair of coils would be suitable for this transformer? number of turns number of turns on primary coil NP on secondary coil NS A 50 1 000 B 240 48 000 C 480 24 D 2000 100

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2020

36 The diagram shows a wire carrying a current in the direction shown. There is a magnetic field acting from left to right. The wire experiences a force acting out of the page. direction of current wire direction of magnetic field The current is now reversed. In which direction does the force on the wire now act? A into the page B out of the page C to the left D to the right

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2020

36 The diagram shows an electromagnet near a coil of wire connected to a voltmeter. The reading on the voltmeter is zero. electromagnet coil soft iron switch V + – The switch is closed. The electromagnet magnetises quickly. What happens to the reading on the voltmeter? A It keeps increasing. B It quickly increases and stays at maximum. C It quickly increases and then decreases. D It stays on zero.

1 marks

Answer: C

This question in 0625/22 Feb/March 2021

37 Which graph shows the voltage output of an a.c. generator with the peaks and zeros correctly labelled? A B peaks peaks voltage V voltage V 0 0 0 time t 0 time t zeros zeros C D peaks peaks voltage V voltage V zeros 0 0 0 time t 0 time t zeros peaks

1 marks

Answer: D

This question in 0625/22 Feb/March 2021

28 Three piles of small nails, P, Q and R, are placed on a bench below three electromagnets. One set of nails is made of copper, one of soft iron and one of steel. Diagram 1 shows the situation when the electromagnets are switched on. Diagram 2 shows the situation when the electromagnets are then switched off. diagram 1 the switches are closed Q R P bench small nails diagram 2 the switches are open small nails R bench P Q Which row correctly identifies the materials from which the nails are made? copper soft iron steel A P Q R B P R Q C Q P R D Q R P

1 marks

Answer: A

This question in 0625/22 May/June 2021

35 A solenoid is connected to a very sensitive ammeter. A rod is inserted into one end of the solenoid. The ammeter shows that there is a small electric current in the solenoid while the rod is moving. solenoid rod A Which rod is being inserted? A a heated copper rod B a magnetised steel rod C an uncharged nylon rod D a radioactive uranium rod

1 marks

Answer: B

This question in 0625/22 May/June 2021

36 The diagram shows a transformer. iron core 550 turns 115 turns output 22 000 V voltage What is the output voltage? A 0.35 V B 2.9 V C 4600 V D 105 000 V

1 marks

Answer: C

This question in 0625/22 May/June 2021

34 What is the function of the split-ring commutator in an electric motor with a single rotating coil? A to enable the motor to function with an a.c. source B to reverse the current in the coil once every revolution C to reverse the current in the coil whenever its plane becomes perpendicular to the magnetic field D to reverse the current in the coil whenever its plane is parallel with the magnetic field

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2021

35 Which graph represents an alternating current (a.c.)? A B current current 0 0 0 time 0 time C D current current 0 0 0 time 0 time

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2021

36 The diagrams show a horizontal wire in a magnetic field. The horizontal wire is firmly held at each end (not shown) and cannot move. The magnets and holder are on a balance. When there is no current in the wire, the reading on the balance is 0.35 g. fixed horizontal wire current direction N S balance N S 0.35 g fixed horizontal wire view from side view from above There is a d.c. current in the wire, as shown. What happens to the reading on the balance? A smaller than 0.35 g B no change C changing from smaller to larger than 0.35 g repeatedly D larger than 0.35 g

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2021

34 The diagram shows a wire between two magnets. An electromotive force (e.m.f.) is induced in the wire when it is moved up between the two magnets. N S Four tests are done. 1 The direction of movement of the wire is reversed. 2 The direction of the magnetic field is reversed. 3 The wire is moved more quickly. 4 The magnetic field strength is decreased. Which tests will induce a smaller e.m.f. in the wire? A 1 and 2 B 1 and 3 C 3 and 4 D 4 only

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2021

35 Four positions of a current-carrying coil in a magnetic field, as in a d.c. motor, are shown. In diagrams 2 and 4, the coil is at an angle of 45 to the field lines. 1 2 3 4 N S N S N S N S coil Which row is correct? turning effect of the forces turning effect of the forces in positions 1 and 3 in positions 2 and 4 A different different B different same C same different D same same

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2021

36 The diagram shows the magnetic field due to a current in a solenoid. direction of current The direction of the current is reversed. Which row describes the effect that this has on the magnitude and on the direction of the magnetic field? magnitude of direction of magnetic field magnetic field A increases changes B increases unchanged C unchanged changes D unchanged unchanged

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2021

35 Which diagram shows the magnetic field around a straight, current-carrying wire? A B current current C D current current

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2021

36 The coil in a d.c. motor is connected to a split-ring commutator. What is the purpose of the split-ring commutator? A to ensure that the coil continues to rotate in the same direction B to ensure that the size of the current in the coil remains constant C to ensure that the size of the turning effect on the coil remains constant D to ensure that the turning effect on the coil changes direction

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2021

35 Two magnets are placed near a current-carrying coil. The diagram shows this experimental arrangement and the current direction in the coil. X Y N S N S Which statement is correct? A Both X and Y are attracted to the coil. B Both X and Y are repelled by the coil. C X is attracted to the coil and Y is repelled. D X is repelled by the coil and Y is attracted.

1 marks

Answer: B

This question in 0625/22 Feb/March 2022

36 Two circuits are set up as shown. The iron rods are placed close together and are able to move. S iron rod iron rod X What happens to the size of the gap at X when switch S is closed? A It decreases. B It decreases then increases. C It increases. D It does not change.

1 marks

Answer: C

This question in 0625/22 Feb/March 2022

37 When a current-carrying conductor is placed in a magnetic field, it experiences a force. Which statement about this force is correct? A It is parallel to both the magnetic field and the direction of the current. B It is parallel to the magnetic field and perpendicular to the direction of the current. C It is perpendicular to the magnetic field and parallel to the direction of the current. D It is perpendicular to both the magnetic field and the direction of the current.

1 marks

Answer: D

This question in 0625/22 Feb/March 2022

35 A magnet is dropped vertically through a solenoid. This induces magnetic poles at both ends of the solenoid. N X X S N S N S diagram 1 diagram 2 diagram 3 Which magnetic poles are induced at position X in diagram 1 and diagram 3? diagram 1 diagram 3 A N pole N pole B N pole S pole C S pole N pole D S pole S pole

1 marks

Answer: C

This question in 0625/21 May/June 2022

36 Which transformer can change a 240 V a.c. input into a 15 V a.c. output? A B 800 turns 40 turns 1000 turns 25 turns C D 2400 turns 15 turns 1200 turns 75 turns

1 marks

Answer: D

This question in 0625/21 May/June 2022

37 What is the purpose of the split-ring commutator in an electric motor? A to ensure that the magnetic field in the motor changes direction every half rotation B to ensure that the magnetic field in the motor stays in the same direction at all times C to ensure that the turning effect on the motor changes direction every half rotation D to ensure that the turning effect on the motor stays in the same direction at all times

1 marks

Answer: D

This question in 0625/21 May/June 2022

40 The diagram shows a stream of B-particles travelling in a line that passes between the poles of a magnet. Oo B-particles In which direction will the B-particles be deflected by the magnet? A __ towards the N pole B_ towards the S pole C into the page D out of the page

1 marks

Answer: D

This question in 0625/21 May/June 2022

35 A coil XY is wound around a cardboard tube. When the S pole of a magnet is pushed into the coil XY, the galvanometer deflects to the left. X Y cardboard tube N S S pole moves in What other movement of the magnet will produce a deflection to the left? A B X Y X Y N S N S S pole N pole moves out moves out C D X Y X Y S N S N N pole S pole moves in moves out

1 marks

Answer: D

This question in 0625/22 May/June 2022

36 Which transformer can change a 240 V a.c. input into a 15 V a.c. output? A B 800 turns 40 turns 1000 turns 25 turns C D 2400 turns 15 turns 1200 turns 75 turns

1 marks

Answer: D

This question in 0625/22 May/June 2022

37 The diagram shows a current-carrying wire in a magnetic field. current N S LEFT RIGHT In which direction is the force acting on the wire? A towards the bottom of the page B to the left C to the right D towards the top of the page

1 marks

Answer: A

This question in 0625/22 May/June 2022

33 The four circuits shown each contain four diodes. In which circuit is the direction of the current in the resistor always from the red terminal to the black terminal? A B 12 V 12 V red black red black terminal terminal terminal terminal C D 12 V 12 V red black red black terminal terminal terminal terminal

1 marks

Answer: A

This question in 0625/23 May/June 2022

35 A wire XY is connected to a resistor R. The wire is moved in the magnetic field between two magnetic poles. In which direction must the wire be moved so that the induced current is in the direction shown? induced current X A S N C D R B Y

1 marks

Answer: B

This question in 0625/23 May/June 2022

36 Which transformer can change a 240 V a.c. input into a 15 V a.c. output? A B 800 turns 40 turns 1000 turns 25 turns C D 2400 turns 15 turns 1200 turns 75 turns

1 marks

Answer: D

This question in 0625/23 May/June 2022

37 The circuit shown consists of a vertical wire, a resistor R and a battery. The magnetic field near the wire is also shown. card card wire carrying current into the page vertical wire R view from above showing the magnetic field Two changes are made to the circuit: ● The polarity of the battery is reversed. ● The resistor R is replaced with another resistor with a lower resistance than R. What effect will these changes have on the magnetic field near the wire? direction of strength of magnetic field magnetic field A opposite same B same weaker C opposite stronger D same stronger

1 marks

Answer: C

This question in 0625/23 May/June 2022

34 The diagram represents a transformer. core primary coil Which row shows materials suitable for making the core and the primary coil? core primary coil A iron copper B iron plastic C steel copper D steel plastic

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2022

35 The diagrams show the magnetic field lines around a wire carrying a current, I. 1 2 I I 3 4 I I Which diagrams are correct? A 1 only B 2 and 3 C 4 only D 1 and 3

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2022

36 Which statement about electromagnetic induction is correct? A A conductor moving parallel to magnetic field lines induces an electromotive force (e.m.f.) in the conductor. B The direction of the induced electromotive force (e.m.f.) opposes the change which produces it. C The induced current is in a direction parallel to the direction of motion producing it. D The induced electromotive force (e.m.f.) decreases when the speed of the conductor moving across the field lines increases.

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2022

31 Diagram 1 is a circuit diagram showing an a.c. power supply connected to four diodes and a resistor. Diagram 2 shows the output voltage from the power supply. diagram 1 diagram 2 voltage 0 R 0 time Which graph correctly shows the voltage–time curve across resistor R? A B voltage voltage 0 0 0 time 0 time C D voltage voltage 0 0 0 time 0 time

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2022

34 Four small compasses are placed around a solenoid. solenoid A current is now switched on in the solenoid. Which diagram shows possible new directions of the compass needles? A B C D

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2022

35 Transformers are used in the transmission of electrical power to houses. Which type of transformer is used at the power station prior to connection to the power lines and which type is used prior to delivery to the houses? power station before houses A step-down step-down B step-down step-up C step-up step-down D step-up step-up

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2022

36 The diagram shows an a.c. generator rotating in a clockwise direction. magnets N S I 2 1 What are the names of parts 1 and 2? 1 2 A brush slip-ring B brush split-ring commutator C slip-ring brush D slip-ring split-ring commutator

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2022

34 Four small compasses are placed around a solenoid. solenoid A current is now switched on in the solenoid. Which diagram shows possible new directions of the compass needles? A B C D

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2022

35 Which metal is used for the core of a transformer? A aluminium B copper C soft iron D steel

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2022

36 The diagram shows a conducting metal rod PQ in the magnetic field between the N pole and the S pole. The rod is connected to a resistor in a circuit. In which direction should rod PQ be moved to induce the current I in the direction of the arrow in the circuit? N A Q C D S P B I

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2022

30 A wire is moved down in a direction perpendicular to the magnetic field. N S Three changes are suggested. 1 The speed of the movement of the wire is increased. 2 The magnetic field strength is decreased. 3 The direction of the magnetic field is reversed. Which changes increase the electromotive force (e.m.f.) induced in the wire? A 1 and 3 B 1 only C 2 and 3 D 3 only

1 marks

Answer: B

This question in 0625/22 Feb/March 2023

31 A wire is moved across a magnetic field. This causes an induced current in the wire. The induced current interacts with the magnetic field to produce a force on the wire. In which direction is this force? A in the direction of the current B in the direction of movement of the wire C in the opposite direction to the current D in the opposite direction to the movement of the wire

1 marks

Answer: D

This question in 0625/22 Feb/March 2023

32 A 100% efficient step-down transformer has primary voltage Vp and primary current Ip. Which row compares the secondary voltage with Vp and the secondary current with Ip? secondary voltage secondary current A greater than Vp greater than Ip B greater than Vp less than Ip C less than Vp greater than Ip D less than Vp less than Ip

1 marks

Answer: C

This question in 0625/22 Feb/March 2023

30 The diagram shows an a.c. generator. N S Y V X The graph shows the potential difference (p.d.) between points X and Y plotted against time. A positive value of p.d. indicates that X is more positive than Y. p.d. between X and Y 0 0 time P Which diagram shows the position of the coil at point P on the graph? A B C D Y Y Y Y X X X X

1 marks

Answer: C

This question in 0625/21 May/June 2023

31 An electron moves into a uniform magnetic field. The arrow shows the initial direction of motion of the electron. The direction of the magnetic field is into the plane of the page. uniform magnetic field electron In which direction does a force act on the electron when it enters the magnetic field? A into the page B out of the page C towards the bottom of the page D towards the top of the page

1 marks

Answer: C

This question in 0625/21 May/June 2023

32 Which statement about a transformer is correct? A There is an alternating current in the iron core from the primary coil to the secondary coil. B An alternating current in the iron core induces an alternating current in the secondary coil. C An alternating current in the primary coil induces a direct current in the secondary coil. D An alternating current in the primary coil induces an alternating voltage across the secondary coil.

1 marks

Answer: D

This question in 0625/21 May/June 2023

30 A step-down transformer is 100% efficient. It has an input voltage of 240 V a.c. and an output voltage of 60 V a.c. The current in the primary coil is 0.50 A. What is the current in the secondary coil? A 0.13 A B 0.50 A C 2.0 A D 8.0 A

1 marks

Answer: C

This question in 0625/22 May/June 2023

31 The diagram shows the pattern of the magnetic field due to the current I in a straight wire. I Y Q P X Which row is correct? relative direction of field strength of field A X greater at P than Q B Y greater at P than Q C X greater at Q than P D Y greater at Q than P

1 marks

Answer: D

This question in 0625/22 May/June 2023

32 In which device is the magnetic effect of a current not used? A electromagnet B loudspeaker C potential divider D relay

1 marks

Answer: C

This question in 0625/22 May/June 2023

30 The diagram shows a wire hanging freely between the poles of a magnet. There is a current in the wire in the direction shown. wire S N current The magnet and current cause a force to act on the wire. In which direction does this force act? A into the page (away from you) B out of the page (toward you) C to the left D to the right

1 marks

Answer: A

This question in 0625/23 May/June 2023

31 Which component forms part of a d.c. motor but not a simple moving coil a.c. generator? A the coil B the brushes C the magnet D the split-ring commutator

1 marks

Answer: D

This question in 0625/23 May/June 2023

32 A transformer has 5500 turns on the primary coil and 500 turns on the secondary coil. The output of the secondary coil is 110 V a.c. and is connected to a heater. The transformer is 100% efficient. The heater produces a power of 132 W. What is the current in the primary coil? A 0.11 A B 0.12 A C 11 A D 12 A

1 marks

Answer: A

This question in 0625/23 May/June 2023

24 Which metal could be used for a permanent magnet and which metal could be used for the core of an electromagnet? permanent core of magnet electromagnet A iron copper B iron steel C steel copper D steel iron

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2023

31 A current in a solenoid produces a uniform magnetic field inside the solenoid. The magnetic field direction is due east. Which changes will produce a stronger magnetic field with a direction due west? A Use a smaller current and turn the solenoid through 180. B Use a smaller current and reverse the current. C Use a larger current and turn the solenoid through 90. D Use a larger current and reverse the current.

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2023

32 A metal rod PQ rests on two horizontal metal wires that are attached to a battery. The rod lies between the poles of a magnet. magnet N Q metal rod P S magnet When the switch is closed, the rod moves to the right. What could be changed so that the rod moves to the left? A Open the switch. B Reverse the battery terminals and exchange the poles of the magnet. C Reverse the battery terminals but without exchanging the poles of the magnet. D Turn the metal rod around (P and Q exchanged).

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2023

33 A transformer in a computer is used to transform the mains voltage of 240 V to 12 V. The number of turns on the secondary coil is 2000. Which statement about the transformer is correct? A It is a step-down transformer and has 100 turns on its primary coil. B It is a step-down transformer and has 40 000 turns on its primary coil. C It is a step-up transformer and has 100 turns on its primary coil. D It is a step-up transformer and has 40 000 turns on its primary coil.

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2023

31 A piece of soft iron XY has a coil of wire wound round it. magnet soft iron S N X Y The N pole of a bar magnet is pulled away from end X which causes an induced current in the coil. The magnet is now turned round so that the N pole is on the left. It is taken to the other end of the soft iron and the N pole is pushed towards end Y. A new current is induced in the coil. Which statement is correct? A The new induced current is in the opposite direction and causes the soft iron to attract the N pole. B The new induced current is in the opposite direction and causes the soft iron to repel the N pole. C The new induced current is in the same direction and causes the soft iron to attract the N pole. D The new induced current is in the same direction and causes the soft iron to repel the N pole.

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2023

32 The diagram shows a wire in the magnetic field between two poles of a magnet. magnet N S wire The current in the wire repeatedly changes between a constant value in one direction and a constant value in the opposite direction, as shown in the graph. current 0 0 time What is the effect on the wire? A The force on the wire alternates between one direction and the opposite direction. B The force on the wire is constant in size and direction. C There is no force acting on the wire at any time. D There is only a force on the wire when the current reverses.

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2023

33 A transformer has Np turns on its primary coil and Ns turns on its secondary coil. The voltage across the primary coil is Vp and the voltage across the secondary coil is Vs. What is the relationship between these four quantities? A Vp  Vs = Np  Ns V N B p = p V N s s V N C p = s V N s p V D p = Np  Ns V s

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2023

31 A simple a.c. generator has a coil rotating in a magnetic field. What happens to the peak electromotive force (e.m.f.) and to the frequency of the a.c. output when the coil is rotated faster? peak e.m.f. frequency A greater greater B greater no change C no change greater D no change no change

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2023

32 A current passes along a wire placed between the poles of a permanent magnet. The wire experiences a force due to the magnetic field. N S What will change the direction of this force? A increasing the current B reversing the current C increasing the strength of the magnetic field D using an electromagnet with the same polarity as the permanent magnet

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2023

33 What is a transformer used for? A changing a direct current into an alternating current B changing the magnitude of an alternating voltage C reducing the frequency of an alternating current D switching off the current in a circuit when there is a fault

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2023

25 The diagram shows a transformer. iron core 550 turns 115 turns output 22 000 V voltage What is the output voltage? A 0.35 V B 2.9 V C 4600 V D 105 000 V

1 marks

Answer: C

This question in 0625/22 Feb/March 2024

33 A beta-particle enters a uniform magnetic field directed into the page and deflects downwards, as shown. region of magnetic field into page Which direction of electric field would also deflect an electron downwards? A into the page B out of the page C down the page D up the page

1 marks

Answer: D

This question in 0625/22 Feb/March 2024

28 When a conductor in a complete circuit cuts across a magnetic field, a current is induced in the conductor. Which statement about the induced current is correct? A The induced current is in the same direction as the motion of the conductor. B The induced current is in the opposite direction to the motion of the conductor. C The direction of the induced current is in the same direction as the magnetic field. D The direction of the induced current opposes the change causing it.

1 marks

Answer: D

This question in 0625/21 May/June 2024

29 The diagram shows a solenoid carrying an electric current. X X Y Y Z Z Which row compares the strength of the magnetic field due to the solenoid at points Y and Z with the strength of the magnetic field at point X? magnetic field magnetic field strength at Y strength at Z A equal to X less than X B equal to X greater than X C greater than X less than X D greater than X greater than X

1 marks

Answer: A

This question in 0625/21 May/June 2024

30 A conducting wire is placed between the poles of a magnet. When an electric current in the wire is in the direction shown, then the force on the wire acts out of the page. wire N S Three statements of different conditions and how the wire is affected are given. 1 When the current is towards the top of the page and the direction of the magnetic field is unchanged, the force produced acts into the page. 2 When the current is towards the bottom of the page and the magnetic field is reversed, the force produced acts into the page. 3 When the current in the wire is alternating, the wire vibrates into and out of the page. Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 0625/21 May/June 2024

31 Which types of electric current are in the primary coil and the secondary coil of a step-up transformer? primary secondary coil coil A a.c. a.c. B a.c. d.c. C d.c. a.c. D d.c. d.c.

1 marks

Answer: A

This question in 0625/21 May/June 2024

31 The diagram shows a simple a.c. generator. The magnet rotates around a fixed coil wound round a fixed iron core. The electromotive force (e.m.f.) output is a sine wave, a series of crests, zeros and troughs. The magnet is shown in three positions, P, Q and R, during its rotation. The magnetic field in the coil is zero at Q but changing most rapidly. position P position Q position R magnet N S S N fixed coil Which statement about the induced e.m.f. in the coil is correct? A The magnitude of the e.m.f. at position Q is larger than that at position P. B The magnitude of the e.m.f. at position Q is zero. C The magnitude of the e.m.f. at position Q is smaller than at position R, but not zero. D The magnitude of the e.m.f. at position R is larger than at position P.

1 marks

Answer: A

This question in 0625/22 May/June 2024

32 A 24 V power supply and a 100% efficient transformer are used to light a 6.0 V, 12 W lamp. What is the current in the power supply? A 0.50 A B 2.0 A C 3.0 A D 8.0 A

1 marks

Answer: A

This question in 0625/22 May/June 2024

32 A transformer is 100% efficient. Which pair of equations are both valid for the transformer? V V A IpVp = IsVs p = s N N p s V V B p = s NpVp = NsVs I I p s V V V V C p = s p = s I I N N p s p s D IpVp = IsVs NpVp = NsVs

1 marks

Answer: A

This question in 0625/23 May/June 2024

31 A metal rod, XY, is placed in a magnetic field so that it is perpendicular to the field, as shown. X Y In which direction is the rod moved so that there is an induced current from Y to X? A left to right B right to left C into the paper, away from the observer D out of the paper, towards the observer

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2024

32 The diagram shows a basic electric motor. X N S Y Z What are the names of the features? X Y Z A axle battery brushes B coil brushes commutator C generator wires transformer D solenoid connectors switch

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2024

33 Two transformers, P and Q, each have 2000 turns on their primary coils and 1000 turns on their secondary coils. Both transformers are 100% efficient. The secondary of transformer P is connected to the primary of transformer Q. Q provides a motor with a current of 0.2 A. What is the current being supplied to the primary of transformer P? A 0.8 A B 0.4 A C 0.1 A D 0.05 A

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2024

31 The diagram shows a wire XY moving upwards in a magnetic field. Y N S X A current is induced in the wire. The current-carrying wire XY experiences a force because of its interaction with the magnetic field. Which row gives the direction of the induced current and the direction of the force experienced by the wire XY? direction of direction of induced current the force A from X to Y downwards B from X to Y upwards C from Y to X downwards D from Y to X upwards

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2024

32 Diagram 1 shows a magnet being pushed into a coil that is connected to a centre-zero sensitive voltmeter. N stationary magnet S N 0 0 0 N S centre-zero sensitive voltmeter S diagram 1 diagram 2 diagram 3 Which row shows the directions of the pointer on the voltmeter when the magnet is as shown in diagrams 2 and 3? diagram 2 diagram 3 A B C D

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2024

33 What is the purpose of the brushes and the split-ring commutator in a d.c. motor? A to change the size of the current B to keep the coil turning in the same direction C to keep the speed of rotation constant D to make the output an alternating voltage

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2024

34 The diagram shows f-particles being directed between the poles of a magnet. B-particles no ) In which direction will the particles be deflected? A into the page Bout of the page C_ towards the bottom of the page D___ towards the top of the page

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2024

31 In an experiment, strong magnetic fields provide a force that keeps charged particles moving with a horizontal circular motion. Positive particles are accelerated clockwise when viewed from above as shown. + In which direction is the magnetic field? A vertically into the page B vertically out of the page C pointing away from the centre of the circular motion D pointing towards the centre of the circular motion

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2024

32 When there is a current in a solenoid, a magnetic field is formed around it. How does the magnetic field change if the current is increased? spacing of field lines strength of field A closer together stronger B closer together weaker C further apart stronger D further apart weaker

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2024

33 The diagram shows the structure of a simple transformer. core primary coil secondary coil Which row shows the correct conditions for the efficiency of the transformer to be as high as possible? primary and core secondary coils A thick copper wire soft iron B thin copper wire soft iron C thick iron wire copper D thin iron wire copper

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2024

30 A wire is moved in the region between the poles of a magnet. wire N pole S pole direction of induced current A current is induced in the wire. In which direction is the wire moved? A horizontally from the N pole to the S pole B horizontally from the S pole to the N pole C perpendicularly into the plane of the paper D perpendicularly out of the plane of the paper

1 marks

Answer: C

This question in 0625/22 Feb/March 2025

31 A fixed resistor is connected to the secondary coil of a step-down transformer. The transformer is 100% efficient. 240 V a.c. A The variable resistor is adjusted so that the current in the fixed resistor decreases by 0.25 A. What is the change to the current in the primary circuit? A It decreases by 0.25 A. B It decreases by less than 0.25 A. C It decreases by more than 0.25 A. D There is no change.

1 marks

Answer: B

This question in 0625/22 Feb/March 2025

32 An electrical device changes the voltage of an electrical supply from 240 V a.c. to 20 V a.c. What is this device? A a generator B a relay C a transformer D a voltmeter

1 marks

Answer: C

This question in 0625/22 Feb/March 2025

33 An a.c. generator is set up so that its coil of wire is perpendicular to the magnetic field. The coil of wire is rotated slowly to produce an alternating electromotive force (e.m.f.). A graph of the induced e.m.f. against time is plotted as the coil rotates. P induced e.m.f. / V Q S O time / s R Which section of the graph represents a rotation of three-quarters of a turn? A OP B OQ C OR D OS

1 marks

Answer: C

This question in 0625/22 Feb/March 2025

29 A wire connected to a resistor R is moved in a magnetic field. A current is induced in the direction shown. In which direction is the wire moved? wire A D B B N S R C induced current

1 marks

Answer: C

This question in 0625/21 May/June 2025

30 Which component is not found in an a.c. generator? A coil of wire B split-ring commutator C magnetic poles D slip rings

1 marks

Answer: B

This question in 0625/21 May/June 2025

32 A simple transformer contains an iron core. What is the function of the iron core in the transformer? A to conduct current from the primary coil to the secondary coil B to enable the secondary coil to act as an electromagnet C to ensure there is a high voltage between the primary coil and the secondary coil D to link the magnetic field in the primary coil to the secondary coil

1 marks

Answer: D

This question in 0625/21 May/June 2025

32 When there is an electric current in a long straight wire, a magnetic field is created around the wire. Which diagram shows the correct pattern and direction of magnetic field lines around a long straight wire carrying current into the page? A B key wire carrying C D current into page

1 marks

Answer: B

This question in 0625/22 May/June 2025

33 The primary voltage supplied to a transformer is 3.0 V. The secondary voltage is 5.0 V and the secondary current is 2.0 A. The transformer is 100% efficient. What is the primary current in the transformer? A 1.2 A B 2.0 A C 3.3 A D 7.5 A

1 marks

Answer: C

This question in 0625/22 May/June 2025

30 The diagram shows a wire moving downwards in a magnetic field between two magnetic poles. There is an induced current in the wire because of the movement. The induced current produces a force on the wire. In which direction is this force? movement of wire downwards A N S D B C wire

1 marks

Answer: A

This question in 0625/23 May/June 2025

31 When the generator shown rotates, there is an a.c. electromotive force (e.m.f.) across the resistor between points P and Q. Diagram 1 shows the position of the coil at time t = 0. The coil rotates clockwise. At time t1, the coil position is horizontal, as shown in diagram 2. diagram 1 diagram 2 rotation N S N S P P V V Q Q The graph shows the output e.m.f. between points P and Q plotted against time. Which point shows the e.m.f. at time t1? A output e.m.f. between P and Q B 0 0 D time C

1 marks

Answer: A

This question in 0625/23 May/June 2025

32 What is the purpose of the split-ring commutator in an electric motor? A to ensure that the magnetic field in the motor changes direction every half rotation B to ensure that the magnetic field in the motor stays in the same direction at all times C to ensure that the turning effect on the motor changes direction every half rotation D to ensure that the turning effect on the motor stays in the same direction at all times

1 marks

Answer: D

This question in 0625/23 May/June 2025

30 The lamps on a bicycle are powered by a simple electrical generator. A permanent magnet rotates around a stationary coil of wire wound on an iron core. Which statement is correct? A The current in the lamps decreases as the speed of rotation increases. B The current in the lamps decreases when the magnet is replaced by a stronger magnet. C The output electromotive force (e.m.f.) will be higher if the gap between the magnet and the coil is bigger. D The output e.m.f. will be higher if there are more turns on the coil.

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2025

31 A current-carrying coil in the magnetic field between the poles of two magnets experiences a turning effect. Which change would decrease the turning effect? A decreasing the distance between the magnets B increasing the current in the coil C using stronger magnets D decreasing the number of turns on the coil

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2025

32 Cables transmit electrical power from the output of the transformer at a power station to the input of another transformer at a substation. cables output input transformer at transformer at power station substation The power at the output of the transformer at the power station is 400 MW. Which situation delivers the most power to the input of the transformer at the substation? potential difference at power station transformer diameter of cables output / kV A 200 large B 200 small C 400 large D 400 small

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2025

30 A length of wire moves across the space between the poles of a magnet. A voltmeter measures the electromotive force (e.m.f.) generated between the two ends of the wire. What gives the highest reading on the voltmeter? speed strength of wire of magnet A fast weak B fast strong C slow weak D slow strong

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2025

31 The diagram shows a simple a.c. generator. N S G H What is connected to G and H so that alternating current can be provided to an external circuit? A cell B commutator C slip rings D soft iron core

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2025

32 The diagrams show the coil in a d.c. electric motor in two positions. As the coil rotates through 180°, the direction of the current in the coil reverses from PQRS to SRQP. Q R R Q P S S P Which part of the motor is responsible for reversing the current? A the brushes B the coil C the magnets D the split-ring commutator

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2025

32 The diagram shows a wire between two magnetic poles. The wire is connected in a circuit with an ammeter. wire N S A The wire is moved downwards, towards the bottom of the page. A current is induced in the wire. In which direction is the force on the wire caused by this current? A towards the bottom of the page B towards the left of the page C towards the right of the page D towards the top of the page

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2025