(a)[3]
The current in the solenoid is switched on once more. A few seconds later, it is switched off. The Hall probe is left in the same position. On the axes of Fig. 7.2, sketch a graph to show how the Hall voltage $V_H$ varies with time $t$.
(b(i))[2]
The Hall probe is now swapped for a small coil. The plane of the coil is parallel to the end face of the solenoid. State Faraday’s law of electromagnetic induction.
(b(ii))[3]
On the axes of Fig. 7.3, sketch a graph to show how the induced e.m.f. $E$ in the coil varies with time $t$ when the current in the solenoid is switched on and then switched off.