Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Electromagnetism
68 practice questions
Topics covered
Practice questions
31–40 of 68
Question 31
3 marks · Normal
Answer and see the solution →You are given a coil of wire, a bar magnet, and a sensitive voltmeter.
Describe a practical experiment to show electromagnetic induction and how you would demonstrate that the induced voltage depends on the speed of movement.
(a)[1 mark]Describe how you would set up the apparatus to show an induced voltage.
(b)[2 marks]Describe what you would do to investigate how the induced voltage changes with speed.
Question 32
1 mark · Easy
Answer and check →What must be true for a transformer to work properly?
- A.The current in the primary coil must be alternating (a.c.).
- B.The secondary coil must be thicker than the primary coil.
- C.The voltage in the secondary coil must be higher than the primary coil.
- D.Both coils must be made of iron.
Question 33
2 marks · Easy
Answer and see the solution →A transformer has 200 turns on its primary coil and 400 turns on its secondary coil. The input voltage is 10 V a.c.
Calculate the output voltage from the secondary coil.
Question 34
3 marks · Easy
Answer and see the solution →The diagram below shows a basic transformer.
A simple transformer with labelled input and output (a)[1 mark]State the name of the part labelled as 'soft iron core'.
(b)[2 marks]Explain why a soft iron core is used in a transformer.
Question 35
3 marks · Easy
Answer and see the solution →A transformer is used to reduce the voltage from a mains a.c. supply of 120 V to 12 V for use in a toy train set. The primary coil has 480 turns.
(a)[1 mark]Is this a step-up or a step-down transformer? Explain your answer.
(b)[2 marks]Calculate the number of turns that should be on the secondary coil.
Question 36
2 marks · Easy
Answer and see the solution →State and explain why transformers only work with alternating current (a.c.) and not with direct current (d.c.).
Question 37
3 marks · Easy
Answer and see the solution →A transformer has 120 turns on its primary coil and 480 turns on its secondary coil. The input voltage is 6 V a.c.
(a)[1 mark]Is this transformer a step-up or a step-down transformer? Explain your answer.
(b)[2 marks]Calculate the output voltage from the secondary coil.
Question 38
3 marks · Easy
Answer and see the solution →Look at the diagram of a transformer below and answer the questions.
Diagram of a transformer (a)[2 marks]Name the part labelled 'core' in the diagram and state its purpose in the transformer.
(b)[1 mark]Is this transformer a step-up or a step-down transformer? Explain your answer.
Question 39
2 marks · Normal
Answer and see the solution →State the purpose of a soft iron core in a transformer.
Question 40
3 marks · Normal
Answer and see the solution →A transformer is used to produce an output voltage of 48 V from a 240 V a.c. mains supply. The primary coil has 960 turns.
Calculate the number of turns needed on the secondary coil to achieve this output voltage.