A conducting circular loop is placed in a uniform magnetic field of 0 . 4   T with its plane…

A conducting circular loop is placed in a uniform magnetic field of 0.4 T with its plane perpendicular to the field. Somehow, the radius of the loop starts expanding at a constant rate of 1 mm s-1. The magnitude of induced emf in the loop at an instant when the radius of the loop is 2 cm will be _______ μV.

Solution

The data given is 

B=0.4 TR=2×10-2 m

It is given that dRdt=10-3 m s-1

Area of the loop is A=πR2

So, dAdt=2πRdRdt

The flux is,

ϕ=2πRdRdt×B

So, the magnitude of emf is 

ε=2×227×2×10-2×10-3×0.4

=5.028×10-5 V=50.28 μV≈50  μV

Asked in: JEE Main 2023 (12 Apr Shift 1)

Practice more Electromagnetic Induction questions on Aicharya