A coil has `2000` turns and area of `70cm^(2)`. The magnetic field perpendicular to the plane of the coil is `0.3 Wb//m^(2)` and takes `0.1` sec to rotate through `180^(0)`. The value of the induced e.m.f. will be

Options

A. 8.4 V
B. 84 V
C. 42 V
D. 4.2 V

Answer

A

Explanation

Change in flux = 2BAN
`therefore` Induced e.m.f. `=(2xx0.3xx200xx70xx10^(-4))/(0.1)`