A wheel with 10 metallic spokes each 0.5 m long is rotated with a speed of 120 rev/min in a plane normal to the horizontal component of earth's magnetic field `H_E` at a place. If `H_E` 0.4 G at the place, what is the induced emf between the axle and the rim of the wheel ? Note that `1G =10^(-4)T.`

Explanation

Induced emf `=(1//2) omega B R^(2)`
`=(1//2)xx4pixx0.4 xx 10^(-4)xx(0.5)^(2)`
`=6.28xx10^(-5)V`