Emf induced in a rod of length l with angular speed in a uniform magnetic field is given by:

E = $$\frac{1}{2}Bl^{2}\omega$$ $$\omega = \frac{2\pi N}{t}$$

E = $$\frac{1}{2}0.2 * 10^{-4} * (0.5)^{2} * \frac{2 * 3.14 * 120}{60}$$

E = $$3.14 * 10^{-5}V$$

The emf induced is independent of the number of spokes as the EMFs across them are in parallel. So it is unaffected by the increase in the number of spokes.

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