A wheel with ten metallic spokes each `0.50 m` long is rotated with a speed of `120 rev//min` in a plane normal to the earth's magnetic field at the place. If the magnitude of the field is `0.4` gauss, the induced e.m.f. between the axle and the rim of the wheel is equal to

Explanation

To solve the problem of finding the induced e.m.f. between the axle and the rim of the wheel, we can follow these steps:

### Step 1: Understand the parameters given in the problem
- Number of spokes (N) = 10
- Length of each spoke (L) = 0.50 m
- Speed of rotation (f) = 120 revolutions per minute (rev/min)
- Magnetic field (B) = 0.4 gauss

...