Question

Figure 9 shows a metallic rod MN of length l = 3 m moving in an external uniform magnetic field, B = `(1/pi)T` which is directed into the plane of this paper.

If the position of the rod changes with time as x = πt, where x is in meter and t is in second, then:

1. Calculate the motional emf developed in the rod.
2. Name the law used to find the direction of induced current.

Answer 1

Given: B = `(1/pi)T`

l = 3 m

v = `dx/dt = (d(pit))/dt` = π ms⁻¹

1. Motional emf (e) = Blv

= `(1/pi) xx 3 xx pi V`

= 3 V

2. The law used to find the direction of the induced current is Fleming’s right-hand rule.