Transformers · CSEC Physics

40 past-paper questions on Transformers, part of Electricity and Magnetism, from every CSEC Physics paper on Quelpr.

1. 1(a)3 marks· CSEC Physics · 1989 · Paper 2Draw a circuit diagram for the experiment. Label the primary and secondary windings.
2. 1(b)(i)1 mark· CSEC Physics · 1989 · Paper 2Find, from the graph, the value of Ip when Is = 1.00 A.
3. 1(b)(iii)3 marks· CSEC Physics · 1989 · Paper 2State and explain what you would have expected the equation to be if the transformer had been an ideal one.
4. 1(b)(iv)1 mark· CSEC Physics · 1989 · Paper 2What would have been the value of Ip for the ideal transformer when Is = 1.00 A?
5. 1(c)(i)2 marks· CSEC Physics · 1989 · Paper 2Describe the first of TWO measures you would take in the construction of a transformer to make its behaviour close to that of an ideal one.
6. 1(c)(ii)2 marks· CSEC Physics · 1989 · Paper 2Describe the second of TWO measures you would take in the construction of a transformer to make its behaviour close to that of an ideal one.
7. 4(b)4 marks· CSEC Physics · 1992 · Paper 2A mechanic states that a transformer cannot be used with the d.c. dynamo to obtain a higher potential difference as transformers work only with alternating current. State whether the mechanic is correct and explain your…
8. 2(v)2 marks· CSEC Physics · 1993 · Paper 2Electricity is produced at 6 600 V a.c. and stepped up to 132 000 V for distribution. State how the potential is raised and give ONE advantage of transmitting at a higher potential.
9. 4(c)(i)5 marks· CSEC Physics · 1995 · Paper 2The symbol for a transformer is shown. Complete the circuit diagram to show how a transformer, together with the components listed below, could be used to charge a 12 V car battery from a 120 V mains supply. Components:…
10. 1(a)3 marks· Physics Q1 1(a)Name the parts labelled X, Y and Z.
11. 1(c)1 mark· Physics Q1 1(c)What does the slope of your graph represent?
12. 1(c)(i)4 marks· Physics Q1 1(c)(i)Use the gradient, S, to calculate the number of turns in the primary, Np, given that the number of turns in the secondary, Ns = 750.
13. 1(d)(i)4 marks· Physics Q1 1(d)(i)Use the gradient, S, to calculate the number of turns in the secondary coil, Ns, given that the number of turns in the primary coil, Np = 85.
14. 1(d)(ii)3 marks· Physics Q1 1(d)(ii)Calculate the current in the secondary winding, if the primary current is 1.6 A.
15. 1(d)(ii)3 marks· Physics Q1 1(d)(ii)If the current in the secondary winding is actually 0.15 A, calculate the efficiency of this transformer.
16. 1(d)(ii)3 marks· Physics Q1 1(d)(ii)Calculate the current in the secondary coil, Is, if the current in the primary coil Ip = 1.8 A.
17. 1(d)(ii)1 mark· Physics Q1 1(d)(ii)How would you know if this was 'an ideal transformer'?
18. 1(d)(iii)3 marks· Physics Q1 1(d)(iii)Calculate the power output, Pout, of the transformer, given that the voltage in the secondary coil, Vs = 55 V.
19. 1(e)3 marks· Physics Q1 1(e)State THREE features of the transformer that enable it to operate efficiently.
20. 1(f)2 marks· Physics Q1 1(f)Use the slope of your graph and the equation I₁ = SI₂ to determine the current I₁ in the primary winding.
21. 1(h)(i)2 marks· Physics Q1 1(h)(i)State TWO major sources of energy loss in transformers.
22. 1(h)(ii)2 marks· Physics Q1 1(h)(ii)Describe the constructional features of commercial transformers which minimize the losses stated in Part (h) (i).
23. 4(c)(iv)1 mark· Physics Q4 4(c)(iv)Deduce what would be observed on the galvanometer if the battery were replaced by a low frequency a.c. supply.
24. 4(c)(v)1 mark· Physics Q4 4(c)(v)How would these observations be affected if the number of turns on the transformer secondary were significantly increased?
25. 5(a)(i)2 marks· Physics Q5 5(a)(i)State TWO advantages of using a.c. to transmit electrical power.
26. 5(a)(ii)4 marks· Physics Q5 5(a)(ii)Draw a diagram of a simple transformer indicating the features which enhance efficiency.
27. 5(b)(i)3 marks· Physics Q5 5(b)(i)If the number of turns in the secondary coil is 900, calculate the number of turns in the primary coil for an ideal transformer.
28. 5(b)(ii)3 marks· Physics Q5 5(b)(ii)Calculate the transmission current for the ideal transformer referred to at (b) (i).
29. 5(b)(iii)3 marks· Physics Q5 5(b)(iii)Calculate the transmission power if the transformer is 70% efficient.
30. 5(c)(i)6 marks· Physics Q5 5(c)(i)How many turns are needed in the secondary winding if the voltage is stepped up from 6.2 V to 15.5 V?
31. 5(c)(ii)6 marks· Physics Q5 5(c)(ii)Given that the current in the primary winding is 10 mA, what power is transmitted to the secondary windings if the transformer is 77% efficient?
32. 6(a)5 marks· Physics Q6 6(a)Explain the principles involved in the workings of the transformer, and how it is able to step down the input voltage.
33. 6(a)(i)4 marks· Physics Q6 6(a)(i)State the name of the parts labelled A, B, C and D in Figure 6.
34. 6(a)(ii)1 mark· Physics Q6 6(a)(ii)Identify the type of transformer shown in Figure 6.
35. 6(a)(iii)1 mark· Physics Q6 6(a)(iii)State the formula that relates voltage, V, to number of turns, n, in a transformer.
36. 6(b)(i)9 marks· Physics Q6 6(b)(i)Calculate the voltage across the secondary coil of the transformer
37. 6(b)(ii)9 marks· Physics Q6 6(b)(ii)Calculate the current in the secondary coil of the transformer
38. 6(b)(ii)2 marks· Physics Q6 6(b)(ii)the voltage across the secondary coil
39. 6(b)(iii)3 marks· Physics Q6 6(b)(iii)the maximum secondary current if the transformer is 100% efficient.
40. 6(c)1 mark· Physics Q6 6(c)High voltages are used to transmit electrical energy over long distances through long-distance cables. State an advantage of using high voltages.