Physics 9702 · AS & A Level · Electromagnetic induction

Electromagnetic induction — practice question

A wire coil lies in a uniform magnetic field with flux density $B$. Its diameter is $3.6\,\text{cm}$ and it has $350$ turns of wire, as shown in Fig. 9.1.
(a(i))[2]

Fig. 9.2 shows how $B$ varies with time $t$. Show that, for the interval from $t = 0$ to $t = 0.20\,\text{s}$, the electromotive force (e.m.f.) induced in the coil is $0.080\,\text{V}$.

(a(ii))[4]

On the axes in Fig. 9.3, plot the way the induced e.m.f. $E$ changes with time $t$ for $t = 0$ to $t = 0.80\,\text{s}$.

(b)[4]

Use laws of electromagnetic induction to explain why a torque acts on the aluminium disc.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Applying $\varepsilon = \frac{\Delta B A N}{t}$

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