Question

A copper disc of radius 0.1 m is rotated about its centre with 20 revolution per second in a uniform magnetic field of 0.1 T with its plane perpendicular to the field. The emf induced across the radius of the disc is-
A. `(pi)/(20)`volt
B. `(pi)/(10)` volt
C. `20 pi`millivolt
D. `100 pi` millivolt

Answer 1

Correct Answer - C
`varepsilon =(BomegaR^(2))/(2)=(0.1xx(2pixx20)(0.1)^(2))/(2)`
`=20 pi xx 10^(-3)` volt