A wheel with 50 metallic spokes each 0.5 m long is rotated with an angular speed of 12 radian /sec, in a plane normal to the earth's magnetic field. If the magnitude of the field is $ 0.5 \times 10^{-4}$ T, calculate the emf induced between the axle and the rim of the wheel.

Question

(a) $ 75 \times 10^{-5} V$
(b) $ 7.5 \times 10^{-5} V$
(c) $ 75 \times 10^{-4} V$
(d) $ 7.5 \times 10^{-4} V$