Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Electromagnetic Induction
61 practice questions
Topics covered
Practice questions
11–20 of 37 · Normal
Question 11
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 12
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 13
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 14
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 15
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.
Question 16
3 marks · Normal
Answer and see the solution →A transformer has an input voltage of 240 V and an input current of 0.50 A. The transformer is 100% efficient. The output voltage is 12 V.
(a)[3 marks]Calculate the current in the output circuit.
Question 17
2 marks · Normal
Answer and see the solution →A student suggests using a transformer with a direct current (d.c.) supply.
(a)[2 marks]Explain why a transformer does not work with d.c.
Question 18
3 marks · Normal
Answer and see the solution →A step-down transformer has a primary input voltage of 120 V and a primary input current of 0.25 A. The transformer is 100% efficient, and the output voltage is 24 V. Calculate the output current of the transformer.
Question 19
2 marks · Normal
Answer and see the solution →Explain why it is important for a transformer to be as efficient as possible when transmitting electricity over long distances.
Question 20
4 marks · Normal
Answer and see the solution →(a)[3 marks]A transformer is used to provide power to a small electronic device. The input voltage is 230 V and the input current is 0.080 A. The transformer is 100% efficient. The output current is 0.46 A.
Calculate the output voltage.
(b)[1 mark]State the formula used for your calculation.