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 1 G = $10^{–4}$ T.

Question

$\begin{array}{1 1} 6.28 \times 10^{-5} V \\ 3.14 \times 10^{-5}V \\ 1.57 \times 10^{-5}V \\ 4.71 \times 10^{-5} V \end{array}$