The spokes of a wheel are made of metal and their lengths are of one metre. On rotating the wheel about its own axis in a uniform magnetic field of `5xx10^(-5)` tesla normal to the plane of the wheel, a potential difference of `3.14 mV` is generated between the rim and the axis. The rotational velocity of the wheel is-

Options

A. 63 rev/s
B. 50 rev/s
C. 31.4 rev/s
D. 20 rev/s

Answer

D

Explanation

`e=1/2 B omega l^(2)`