Thin wire, covered in plastic insulation, is used to make a solenoid (long coil). The solenoid is connected to a sensitive ammeter. Fig. 10.1 shows the N-pole of a steel magnet placed next to the solenoid. [Figure 10.1] Point X and point Y are on the axis of the solenoid.

1. (a)(i)Explain why plastic is an electrical insulator.[1]
2. (a)(ii)1.Explain why the magnet is not made from aluminium,[1]
3. (a)(ii)2.iron.[1]
4. (b)(i)In one experiment, the magnet in Fig. 10.1 is moved to the left and passes into the solenoid. The N-pole of the magnet travels from Y to X at a constant speed. As it moves, the ammeter shows a small current. Explain why there is a current in the solenoid when the magnet is moving.[3]
5. (b)(ii)1.The N-pole travels from Y to X in 0.14s. As it moves, the current shown on the ammeter is 0.045 mA. The resistance of the solenoid is 1.2 Ω. Calculate the potential difference (p.d.) across the solenoid, potential difference =[2]
6. (b)(ii)2.the charge that passes through the solenoid as the N-pole moves from Y to X. charge =[2]
7. (c)(i)In a second experiment, the speed of the N-pole is greater than its speed in the first experiment. It now takes only 0.070s to travel from Y to X. A current in the same direction is shown on the ammeter. State and explain how the size of this current compares with the size of the current in the first experiment.[2]
8. (c)(ii)The same quantity of charge passes through the coil in both the first and second experiments. Explain why this is the case.[1]
9. (d)State two ways in which the equipment shown in Fig. 10.1 can be used to produce a current in the solenoid that is in the opposite direction. 1. 2.[2]

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