Question

A copper disc of radius 0.1 m rotates about its centre with 10 revolutions per second in a uniform magnetic field of 0.1 Tesla. The emf induced across the radius of the disc is

• A. $\frac{\pi}{10}V$
• B. $\frac{2\pi}{10}V$
• C. 10 πMv
• D. 20 πMv

Answer 1

Answer: (C)

10 πMv

Answer 2

The induced emf between centre and rim of the rotating disc is

$E = \frac{1}{2}B\omega R^{2} = \frac{1}{2} \times 0.1 \times 2\pi \times 10 \times (0.1)^{2} = 10\pi \times 10^{- 3}volt$