1. Diagram 1 shows an a.c. generator. The coil is turning as shown.

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?
2. The diagram shows the arrangement of the coil, armature and contacts of a relay.
Which diagram shows this arrangement when there is no current in the coil?
A B.
.

C. D.

3. The diagram represents a magnetic field.

What causes this field?

A. A bar magnet
B. A solenoid carrying a current
C. A straight wire carrying a current
D. Two north poles close together
4. The diagram shows a simple d.c. electric motor which is rotating.

Which change makes the motor rotate more quickly?

A. Increasing the number of turns on the coil
B. Removing the magnets
C. Reversing the battery
D. Reversing the polarity of the magnets

5. 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.
.

C. D
.

6. 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. 2000 60 000
B. 2000 600 000
C. 60 000 2000
D. 600 000 2000
7. 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.

8. The diagram shows a current-carrying conductor in a magnetic field.

Which arrow shows the direction of the force acting on the conductor?

9. 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.
10. The diagram shows a coil of wire between the poles of a magnet.

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

11. 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 400kV transmission system, a smaller proportion of the energy is used to heat the
atmosphere than with a 240 V system.

12. Either a fuse or a circuit-breaker can be used to protect electrical cables from large currents that
could cause overheating.

When a fuse is used, where should it be connected, and when a circuit-breaker is used, where
should it be connected?
Position of fuse Position of
circuit-breaker
A. X X
B. X Y
C. Y X
D. Y Y
13. There is a current of 3.0A 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.

14. A wire is placed in a strong magnetic field. When a current is passed through the wire it moves
upwards, as shown.

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

15. In this circuit, a component at X automatically protects the wiring from overheating if there is a
fault.

Which row indicates components that are suitable?

Circuit breaker fuse switch
A. ✓ ✓ ✓ Key
B. ✓ ✓ ✗ ✓ = suitable
C. ✓ ✗ ✓ ✗ = not suitable
D. ✗ ✓ ✗
16. The diagram shows a simple transformer with an input of 240V and an output of 40V.
There are 600 turns on the primary coil.

How many turns are there on the secondary coil?

A. 100
B. 320
C. 400
D. 3600

17. 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.

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
18. A wire is placed between the poles of a horseshoe magnet. There is a current in the wire in the
direction shown, and this causes a force to act on the wire.

Three other arrangements P, Q and R of the wire and magnet are set up as shown.

Which arrangements cause a force in the same direction as the original arrangement?
A. P, Q and R
B. P and Q only
C. P only
D. R only

19. (a) Describe how to demagnetise a bar magnet using alternating current (a.c.) in a coil.

(b) Fig. 9.1 shows a simple direct current (d.c.) motor.

 (i) Explain the purpose of the split-ring commutator.

(ii) The voltage of the power supply is increased.

State the effect this has on the motor.

20. (a) The electrical energy produced by a power station is transmitted over long distances at a very
high voltage.
Explain why a very high voltage is used.

(b) Fig. 10.1 represents a transformer.

(i) The primary coil P has 4000 turns and an input of 120V. The secondary coil S has an
output of 9.0V.
 Calculate the number of turns in the secondary coil.

number = .........................................................
(ii) State a suitable material for the core of the transformer.

21. (a) Fig. 10.1 shows a straight wire AB placed in the magnetic field between the poles of a
magnet. The ends of AB are connected to a galvanometer.

When AB is moved vertically, the needle of the galvanometer shows a deflection.

State three factors that affect the size of the deflection.
1 ...............................................................................................................................................
2 ...............................................................................................................................................
3 ...............................................................................................................................................
(b) Fig. 10.2 shows a transformer.

(i) The primary coil P has 8000 turns and an input of 240V. The secondary coil S has an output
of 12V.
Calculate the number of turns in the secondary coil.
 number = .........................................................
(ii) A circuit containing a resistor is connected to the terminals A and B.
A direct current (d.c.) is required in this resistor.
On Fig. 10.2, draw this circuit.

22. (a) Fig. 9.1 shows a coil ABCD with two turns. The coil is in a magnetic field.

When there is a current in the coil, the coil experiences a turning effect.
(i) Explain why there is a turning effect.

(ii) The value of the current is 3A. Place one tick in each column of the table to indicate how
the turning effect changes with the change described.
turning effect number of turns current strength of
on coil increased to 9A magnetic
increased to six field decreased by a
factor of 2
decreased by factor of 4
decreased by factor of 3
decreased by factor of 2
no change
increased by factor of 2
increased by factor of 3
increased by factor of 4

(b) Fig. 9.2 shows a magnet held just below a vertical coil connected to a galvanometer.
 The magnet is released.
(i) State any effect on the galvanometer.

(ii) State any effect on the magnetic field produced by the coil.

23. Fig. 8.1 shows a circuit that contains a battery of electromotive force (e.m.f.) 6.0V, an ammeter,
a 20Ω resistor and component X.

(a) (i) State the name of component X.

.......................................................................................................................................
(ii) The potential difference (p.d.) across the 20Ω resistor is measured with a voltmeter.
On Fig. 8.1, draw the symbol for this voltmeter connected to the circuit.
(b) The p.d. across the 20Ω resistor is varied from zero to 6.0V. For each value of p.d. a
corresponding current is measured.
On Fig. 8.2, draw a line to indicate how the current measured by the ammeter depends on
the p.d. across the 20Ω resistor.

(c) A second resistor is connected into the circuit in parallel with the 20Ω resistor.
(i) State how the combined resistance of the two resistors in parallel compares with the
resistance of each of the resistors on its own.

(ii) The p.d. across the two parallel resistors is changed and the current in the battery for
each value of the p.d. is measured. A second line could be drawn on Fig. 8.2 to indicate
how the current measured by the ammeter depends on the p.d. across the two resistors
in parallel.
State how the second line differs from the original line. You are not expected to draw this
second line.
24. (a) (i) Fig. 8.1 shows a positively charged cube of insulating material. The cube is fixed to a
piece of wood that is floating on water. A negatively charged rod is held above the piece of
wood and brought close to the cube, as shown.

State and explain any movement of the piece of wood.

...........................................................................................................................................
...........................................................................................................................................

(ii) Fig. 8.2 shows two cubes of insulating material. One is positively charged and the other
is negatively charged. The cubes are fixed to a piece of wood that is floating on water.
Charged rods are held above the piece of wood and brought close to the cubes, as
shown.
State and explain any movement of the piece of wood.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(b) In terms of a simple electron model, describe the differences between conductors and
insulators.
conductors ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
insulators ..................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
(c) On Fig. 8.3, draw the electric field pattern around a single point positive charge.
25. Fig. 7.1 shows three identical lamps and an ammeter connected to a power supply.

The switches are closed. Each lamp is rated at 60W and operates at its normal working voltage
of 110V.
(a) Calculate:
(i) the current in each lamp
current = ............................................................
(ii) the current in the ammeter
current = ...........................................................
(iii) the voltage of the power supply.
voltage = ...........................................................
(b) (i) Calculate the resistance of the filament of one of the lamps when working normally.
resistance = ...........................................................
(ii) Another lamp X has a filament with twice the resistance of each lamp in the circuit of
 Fig. 7.1. The material and the temperature of the filament in lamp X is the same as the
filaments in the lamps in Fig. 7.1.
In Table 7.1, tick any box in the right-hand column that shows a possible difference
between the filament of lamp X and a filament of one of the lamps in the circuit.
Table 7.1
X has half the length
X has twice the length
X has one quarter the area of cross-section
X has half the area of cross-section
X has two times the area of cross-section
X has four times the area of cross-section

26. (a) A transformer consists of two coils of wire wound on a core.

(i) Suggest the material from which the two coils are made. State the reason for using this
material.
material ..............................................................................................................................
reason ................................................................................................................................

(ii) Suggest the material from which the core is made. State the reason for using this material.
material ..............................................................................................................................
reason ................................................................................................................................

(b) Fig. 8.1 represents the system of transmission of electrical energy from a power station to a
home that is a long distance away.

(i) State the difference between transformer X and transformer Y.

.......................................................................................................................................
(ii) Explain why a very high voltage is used for transmission over large distances.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................
(iii) Suggest why the voltage for use by a home consumer is 240V, and not a much higher
value.
...........................................................................................................................................
27. Fig. 9.1 shows a graph of current against potential difference (p.d.) for a filament lamp.

(a) State what happens to the resistance of the filament of the lamp as the p.d. changes
(i) from 0V to 1.0V,
.......................................................................................................................................
(ii) from 1.0V to 8.0V.
.......................................................................................................................................
(b) At normal brightness, the p.d. across the lamp is 8.0V.
Calculate, for normal brightness,
(i) the resistance of the lamp,
resistance = ...........................................................
(ii) the power of the lamp.
power = ...........................................................
(c) Five of these lamps, operating at normal brightness, are connected in parallel to a power
supply.
 Determine
(i) the electromotive force (e.m.f.) of the power supply,
e.m.f. = ...........................................................
(ii) the current from the power supply.
current = ...........................................................

28. (a) Describe, in terms of particles and the terminals of the battery, the movement of charge in an
electric circuit.
...................................................................................................................................................
...............................................................................................................................................[2]
(b) Fig. 10.1 shows a lightning flash between a cloud and the ground beneath.
The charge built up on the cloud before the lightning flash is 0.60 C. This charge is completely
transferred to the ground by the lightning flash in 5.0 × 10–5 s (0.000050 s).
(i) Calculate the current between the cloud and the ground.
current = ...........................................................
(ii) The potential difference (p.d.) between the cloud and the ground during the lightning flash is
2.5 × 108 V.
Calculate the energy transferred during the lightning flash.
energy = ...........................................................
(iii) Suggest what happens to the energy calculated in (b)(ii).
...........................................................................................................................................
.......................................................................................................................................