Physics 9702 · AS & A Level · Electromagnetic induction
Electromagnetic induction — practice question
A Hall probe is positioned close to one end of a solenoid wound around a soft-iron core, as illustrated in Fig. 9.1. The current in the solenoid is then turned on. The Hall probe is turned until the voltmeter reading $V_H$ reaches a maximum. The current in the solenoid is next changed, so that the magnetic flux density alters. The way the magnetic flux density $B$ at the Hall probe varies with time $t$ is shown in Fig. 9.2. At time $t = 0$, the Hall voltage is $V_0$.
(a)[2]
On Fig. 9.3, add a line to represent how the Hall voltage $V_H$ varies with time $t$ from $t = 0$ to $t = t_4$.
(b)[3]
In (a), the Hall probe is now swapped for a small coil of wire joined to a sensitive voltmeter, as shown in Fig. 9.4. The magnetic flux density, normal to the plane of the small coil, is again altered as shown in Fig. 9.2. On Fig. 9.5, sketch a line to show how the e.m.f. $E$ induced in the small coil varies with time $t$ from $t = 0$ to $t = t_4$.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$t_0 \to t_1$ horizontal section at non-zero $V_H$” …