An aircraft with a wing span of 50 m flies horizontally at a speed of \({\text{200 m}}\,{{\text{s}}^{ - 1}}\). The vertical component of the Earth’s magnetic field at the plane’s position is \({\text{10 }}\mu {\text{T}}\).

What electromotive force (emf) is induced between points A and B on the aircraft?

A.     0.1 V

B.     1 V

C.     10 V

D.     100 V

A

As all the responses have the same significant figures this is clearly a question about powers of ten rather than an aeroplane flying through a magnetic field. The majority of candidates understood this and selected the correct response of A.