Question

A copper disc of radius $0.1$m is rotated about its center 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?

Answer 1

Emf induced is given by$=\frac{1}{2}B\omega R^2$---(1) where B=magnetic field=0.1T; $\omega$=angular velocity=20 revolution per second and R=radius of the disc=0.1 m

Now putting the above mentioned values in equation 1

emf$=\frac{1}{2}0.1\times 2\pi \times 20\times (0.1{)}^2=0.0628$