Physics 9702 · AS & A Level · Electromagnetic induction

Electromagnetic induction — practice question

(a)[2]

State Faraday’s law for electromagnetic induction.

(b(i))[2]

Fig. 7.1 shows a coil at rest in a uniform magnetic field parallel to the coil axis. A centre-zero voltmeter is connected across the coil. The flux density $B$ of the uniform magnetic field changes with time $t$ as shown in Fig. 7.2. The coil has $340$ turns, each with cross-sectional area $3.2 \times 10^{-4}\,\text{m}^2$. Calculate the maximum magnetic flux through one turn of the coil.

(b)

Fig. 7.1 shows a coil at rest in a uniform magnetic field parallel to the coil axis. A centre-zero voltmeter is connected to the coil. The flux density $B$ of the uniform magnetic field varies with time $t$ as shown in Fig. 7.2. The coil has 340 turns, each of cross-sectional area $3.2 \times 10^{-4}\,\text{m}^2$.

(b(ii))[3]

Determine the greatest rate of change of magnetic flux linkage in the coil.

(b(iii))[1]

State the largest electromotive force (e.m.f.) $V_0$ induced across the coil.

(b(iv))[3]

On Fig. 7.3, sketch how the e.m.f. $V$ induced across the coil varies with $t$ from $t = 0$ to $t = 6.0\,\text{ms}$.

(b(v))[3]

The change of $V$ with $t$ may be represented by $V = A\sin Bt$, where $A$ and $B$ are constants. Determine the values of $A$ and $B$. Give units with your answers.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: Induced e.m.f. is proportional to rate of change of magnetic flux linkage

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI