1
1 Diagram A shows a wire passing through a card. There is a large electric current in the wire in the
direction shown. Diagram B shows the same arrangement when viewed from above the card.
card
large
current
card
Diagram A Diagram B
There is a pattern of magnetic field lines around the wire due to the current in the wire.
On diagram B, draw the pattern and direction of the magnetic field as if viewed from above the
card. [3]
[Total: 3]
2 The diagram shows a magnet on the end of a spring and a coil of wire connected to a sensitive
centre-zero galvanometer. The magnet can move freely through the coil.
spring
coil of wire
N
centre-zero
galvanometer
S
2
(a) The magnet is pulled down and released.
Describe and explain what happens to the needle of the sensitive galvanometer.
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(b) The magnet is replaced with a stronger magnet.
State the effect of using a stronger magnet on what happens to the needle of the galvanometer.
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........................................................................................................................................... [1]
[Total: 5]
3 The diagram shows the same bar magnets with a coil of wire between them.
direction of
rotation handle
N S
galvanometer
A
(a) The coil of wire is rotated in the direction shown in the diagram.
On the diagram, draw an arrow to show the direction of the current in the coil. Explain your
answer.
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........................................................................................................................................... [2]
3
(b) Explain how rotating the coil in the diagram continuously causes the galvanometer needle to
show an alternating current.
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........................................................................................................................................... [4]
[Total: 6]
4 The diagram shows a horizontal conducting wire XY between two opposite magnetic poles. Wire
XY forms a circuit with an ammeter.
(a) Y
wire
N X
S
A
The wire XY is moved and there is a deflection on the ammeter that indicates there is a current
in the wire from X to Y.
On the table below, tick one box to indicate the direction of the movement of the wire XY.
Explain your answer.
to the bottom to the top of
into page out of page to the left to the right
of the page the page
explanation .......................................................................................................................
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........................................................................................................................................... [3]
4
(b) State what is observed on the ammeter when the wire XY is moved
(i) in the opposite direction to part (a) ...............................................................................
(ii) in the same direction as part (a) but at a greater speed ............................................. [2]
[Total: 5]
5 The diagram represents a current in a wire. The current is into the plane of the paper.
(a) Draw the pattern of the magnetic field produced around the wire. Show clearly the direction
of the magnetic field.
[2]
(b) The direction of the current in the wire is reversed. The magnitude of the current is unchanged.
State the effect that reversing the current has on the magnetic field produced.
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........................................................................................................................................... [1]
[Total: 3]
5
6 An electromagnet consists of a solenoid X that is made of copper wire. The solenoid contains an
iron core.
The diagram shows the electromagnet inside a second solenoid Y.
Describe and explain what happens in solenoid Y when solenoid X is connected to an alternating
current (a.c.) power supply.
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.................................................................................................................................................. [3]
[Total: 3]
7 The diagram shows a simple direct current (d.c.) electric motor. The coil rotates about the axis
when there is a current in the coil. The coil is connected to the rest of the circuit by the brushes.
6
(a) On the diagram, draw a pair of arrows to show which way the coil rotates. Explain the direction
you have chosen.
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........................................................................................................................................... [3]
(b) On the diagram, draw an arrow to show the direction in which electrons flow through the
coil. [1]
(c) Explain why the electrons flow in the direction you have shown in (b).
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........................................................................................................................................... [1]
[Total: 5]
7
8 Diagram A shows a simple alternating current generator.
diagram A
On diagram B, sketch a graph to show how the electromotive force (e.m.f.) induced varies with
time for one revolution of the coil. Assume that the coil starts in the horizontal position, as shown
in diagram A.
Label the points on the time axis where the coil has completed 1/4 revolution and 3/4 revolution.
diagram B
[3]
[Total: 3]
8
9 A student turns the handle of an alternating current (a.c.) generator and the coil rotates.
The diagram represents the structure of the a.c. generator.
There is an alternating voltage output between the two terminals.
Explain why rotating the coil produces an output voltage.
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.................................................................................................................................................. [3]
[Total: 3]
10 The diagram shows the coil ABCD of an a.c. generator between two magnetic poles.
9
(a) On the diagram, draw a straight arrow to indicate the direction in which side AB of the coil is
moving. Label this arrow M. [1]
(b) Deduce the direction of the current induced in side AB of the coil and explain your reasoning.
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........................................................................................................................................... [2]
[Total: 3]
