Question

A 10 meter long wire is kept in east west direction. It is falling down with a speed of 5 m/s, perpendicular to the horizontal component of earth’s magnetic field of 0.30 x 10^-4 Wb/m² . 

(i) what is the momentary p.d induced between the ends of the wire? 

(ii) which end of the wire will be at a higher potential?

Answer 1

(i) If a wire, of length l , move perpendicular to a magnetic field B, with a velocity v, the emf induced will be given by

(ii) According to fleming left hand rule, the magnetic force on the electrons, in the wire, in the magnetic field will act towards west. Hence electrons will more to the western end of the wire, therefore the eastern end of the wire will be a higher (positive) potential.