A solenoid S is wound on a soft-iron core, as shown in [Figure 9.1]. A coil C having 120 turns of wire is wound on to one end of the core. The area of cross-section of coil C is 1.5 cm². A Hall probe is close to the other end of the core. When there is a constant current in solenoid S, the flux density in the core is 0.19 T. The reading on the voltmeter connected to the Hall probe is 0.20 V. The current in solenoid S is now reversed in a time of 0.13 s at a constant rate.

1. (a)State Faraday's law of electromagnetic induction.[2]
2. (b)(i)Calculate the reading on the voltmeter connected to coil C during the time that the current is changing. reading = ........................................................... V[2]
3. (b)(ii)1Complete the voltmeter readings for the coil C/V row in [Figure 9.2].[1]
4. (b)(ii)2Complete the voltmeter reading for the Hall probe/V row in the 'during current change when current is zero' column in [Figure 9.2].[1]
5. (b)(ii)3Complete the voltmeter reading for the Hall probe/V row in the 'after current changes' column in [Figure 9.2] (including sign and magnitude).[2]

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