Electromagnetic Induction (Edexcel GCSE Combined Science: Physics): Exam Questions

Exam code: 1SC0

36 mins6 questions
1a
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4 marks

Higher Tier Only

Figure 1 shows a labelled transformer supplying homes in a village with electricity from a power cable.

7-3-e-1a-transformer-question

Figure 1

Complete the following sentences using words from the box. 

Each word can be used once, more than once or not at all.

cobalt

direct

input

secondary

output

primary

nickel

iron

alternating

Part W labels the input .............................. current.

Part X is the .............................. coil.

Part Y is the .............................. coil.

Part Z is made from .............................. .

1b
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2 marks

Higher Tier Only

(i) State the type of transformer shown in the diagram in part (a).

[1]

(ii) Explain how the diagram shows this type of transformer.

[1]

1c
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1 mark

Higher Tier Only

Compare the voltage in each coil of the transformer in the diagram in part (a).

2a
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1 mark

Higher Tier Only

The national grid allows power to be efficiently delivered across the UK.

Describe where a step-up transformer is used as part of the National Grid.

2b
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5 marks

Higher Tier Only

A teacher writes a note about a transformer but intentionally misses out some words.

Complete the following sentences using the correct words from the box.  

coil

core

current

ends

magnetic

wire

A transformer works because an alternating .............................. in the primary .............................. produces a changing .............................. field in the ..............................  and then in the secondary coil.

This induces an alternating potential difference across the .............................. of the secondary coil.

2c
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2 marks

Higher Tier Only

Explain why it is beneficial for the current in power cables to be small.

3a
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3 marks

Higher Tier Only

Figure 1 shows a magnet passing through a coil of wire connected to an ammeter.

7-3-e-3a-generator-effect--

Figure 1

Explain why the ammeter shows a non-zero reading.

3b
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1 mark

Higher Tier Only

A student moves the magnet towards the coil, from right to left. 

Describe the force they experience while moving the magnet.

3c3 marks

Higher Tier Only

The student performs different actions and records the different ammeter readings they make for each action. 

Use statements from the box to describe the ammeter reading for each action. The first one has been completed for you. 

Needle doesn't move

Needle moves to 0.8 A

Needle moves to −0.4 A    

 

Action of student

Reading on ammeter

Hold magnet still and move coil slowly towards magnet

Needle moves to 0.8 A

Hold magnet still inside the coil    

 

Move the magnet and coil together very quickly    

 

Flip the magnet around and move slowly towards the coil

 

14 marks

A student uses a plotting compass to investigate the magnetic field around a wire.

Figure 10 shows the wire going straight through a card.

compasses

Figure 10 shows the compass needle when there is no current in the wire.

(i) Which of these shows a possible direction of the compass needle when there is a current in the wire going from P to Q?

compasses-2

[1]

(ii) Describe how the student could develop the investigation to find the shape of the magnetic field produced by the current.

[3]

24 marks

Higher Tier Only

There is an alternating current of 3 A in the primary coil of a transformer.

There is an alternating current of 6 A in the secondary coil of the transformer.

The transformer is 100% efficient.

i) The size of the potential difference (voltage) across the secondary coil is

A twice the size of the current in the primary coil

B half the size of the current in the primary coil

C twice the size of the voltage across the primary coil

D half the size of the voltage across the primary coil

[1]

ii) Explain how an alternating current in the primary coil causes an alternating current in the secondary coil of the transformer.

[3]

3a3 marks

Complete the following sentences using one of the phrases from the box below. 

efficiency is reduced

the national grid

a power station

heat loss is reduced

a transformer

(i) Electrical power is generated at .............................................

[1]

(ii) Electricity is transmitted over long distances by transmission

lines that are part of.............................................................

[1]

(iii) Electricity is transmitted at high voltages so that......................

[1]

3b1 mark

Which statement is true for transformers?

  • Transformers can only step-up voltages.

  • Transformers can only step-down voltages.

  • Transformers can work with direct current.

  • Transformers have primary and secondary coils.

3c2 marks

In a small transformer

  • the primary voltage is 230 V

  • the primary current is 0.020 A

  • the secondary voltage is 5.0 V

Calculate the secondary current.

Use the equation

I subscript s equals fraction numerator V subscript p cross times I subscript p over denominator V subscript s end fraction