Physics 9702 · AS & A Level · Electromagnetic induction
Electromagnetic induction — practice question
An aircraft is travelling horizontally at a steady speed $v$ through 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 $68\,\text{m}$. While the aircraft passes through the magnetic field, an electromotive force (e.m.f.) of $0.54\,\text{V}$ is induced across the wingtips P and Q.
(a)[2]
State Faraday’s law for electromagnetic induction.
(b(i))[2]
Calculate the magnetic flux cut by the wings of the aircraft in a time of $15\,\text{s}$. Give a unit with your answer.
(b(ii))[2]
Determine the area of flux cut by the wings during a time of $15\,\text{s}$.
(b(iii))[2]
Use your answer in (b)(ii) to find the speed $v$ of the aircraft.
(b(iv))[3]
Explain, using Lenz’s law of electromagnetic induction, which of the wingtips P and Q is at 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: “(induced) e.m.f. is in direct proportion to the rate” …