Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
THE TRANSFORMER
15 practice questions
Practice questions
11–15 of 15
Question 11
4 marks · Normal
Answer and see the solution →The diagram shows a transformer. The secondary coil has 300 turns and produces a voltage of 15 V.
(a)[3 marks]The primary coil has 1200 turns. Calculate the input voltage.
(b)[1 mark]State whether this transformer is step-up or step-down. Give a reason for your answer.
Question 12
1 mark · Normal
Answer and check →Which change would increase the output voltage of a transformer, assuming the input voltage stays the same?
- A.Increase the number of turns on the secondary coil
- B.Decrease the number of turns on the secondary coil
- C.Increase the number of turns on the primary coil
- D.Use d.c. instead of a.c.
Question 13
3 marks · Normal
Answer and see the solution →A student investigates transformers using different numbers of turns on the secondary coil, measuring output voltages. Her results:
Transformer investigation results Turns on Secondary Coil Output Voltage (V) 100 4.0 200 8.1 300 12.0 400 15.8 (a)[1 mark]Describe the relationship between the number of turns on the secondary coil and the output voltage.
(b)[2 marks]Estimate the output voltage if the secondary coil had 500 turns.
Question 14
4 marks · Normal
Answer and see the solution →A transformer is used to power a device that needs 6 V a.c. from the mains (230 V a.c.). The current in the primary coil is 0.10 A. Assume the transformer is 100% efficient.
(a)[3 marks]Calculate the current in the secondary coil.
(b)[1 mark]Explain why the secondary current is greater than the primary current.
Question 15
3 marks · Normal
Answer and see the solution →Describe two reasons why thick, insulated copper wire and a plastic-coated soft iron core are used in transformer construction.