Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
USING TRANSFORMERS TO CHANGE VOLTAGES
15 practice questions
Practice questions
1–7 of 7 · Normal
Question 1
4 marks · Normal
Answer and see the solution →A transformer has 150 turns on its primary coil and 450 turns on its secondary coil. The input alternating voltage is 12 V.
Calculate the output voltage across the secondary coil.
Question 2
3 marks · Normal
Answer and see the solution →Explain why transformers cannot be used with direct current (d.c.).
Question 3
1 mark · Normal
Answer and see the solution →Which part of a transformer links the magnetic field between the two coils?
- A.Plastic casing
- B.Copper wires
- C.Soft iron core
- D.Steel rod
Question 4
4 marks · Normal
Answer and see the solution →A step-down transformer is used to supply 6 V to a device. The primary coil has 240 turns and the secondary coil has 40 turns. What is the input voltage supplied to the primary coil?
Question 5
3 marks · Normal
Answer and see the solution →The table shows data for four transformers. Complete the table by filling in the missing voltages using the transformer equation.
Primary voltage (V) Secondary voltage (V) Primary turns Secondary turns 15 300 600 9 450 150 6 80 40 Question 6
4 marks · Normal
Answer and see the solution →Figure 1 shows a transformer used to supply power to a small device.
Figure 1. Transformer structure. (a)[1 mark]Label the primary and secondary coils on Figure 1.
(b)[3 marks]Explain why the core is made from soft iron and not another material.
Question 7
4 marks · Normal
Answer and see the solution →The primary coil of a transformer is supplied with 230 V and there is a current of 0.1 A in the primary. If the secondary voltage is 23 V, and the transformer is 100% efficient, calculate the secondary current.