Physics 9702 · AS & A Level · Electromagnetic induction
Electromagnetic induction — practice question
An aircraft is travelling horizontally at a constant speed $v$ in the Earth’s magnetic field, as illustrated in Fig. 7.1. At the aircraft’s position, the vertical component of the Earth’s magnetic field is $38\,\mu\text{T}$ directed towards the ground. The separation between the wingtips P and Q of the aircraft is $68\,\text{m}$. As the aircraft passes through the field, an electromotive force (e.m.f.) of $0.54\,\text{V}$ is induced between the wingtips P and Q.
(a)[2]
State Faraday’s law for electromagnetic induction.
(b(i))[2]
Calculate the magnetic flux intercepted by the aircraft’s wings in a time of $15\,\text{s}$. Give a unit with your answer.
(b(ii))[2]
Determine the area of flux swept out by the wings in a time of $15\,\text{s}$.
(b(iii))[2]
Use your answer in (b)(ii) to determine the aircraft’s speed $v$.
(b(iv))[3]
Use Lenz’s law of electromagnetic induction to explain which of wingtips P and Q has the higher induced potential.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “The (induced) e.m.f. is (directly) proportional to the rate” …