A wheel has three spokes and is an uniform magnetic field perpendicular to its plane, with the axis of rotation of the wheel parallel to the magnetic field. When the wheel rotates with a uniform angualr velocity `omega`, the emf induced between the centre and rim of the wheel is `'e'`. If another wheel having same radius but with six spokes is kept in the same field and rotated with a uniform angular velocity `'omega//2'`, the emf induced between the centre and the rim will be

Options

A. 2
B. e/2
C. 2e
D. e/4

Answer

B

Explanation

`e=B(dA)/(dt)=1/2Bomegar^2`
`therefore` In every spokes same emf developed, and cycle, spokes is equivalent to parallel combination of cells.