Question

A closed coil of 40 turns and of area 200 cm2, is rotated in a magnetic field of flux density 2 Wb m-2. it rotates from a position where its plane makes an angle of 30° with the field to a position perpendicular to the field in atime 0.2 sec. Find the magnitude of the emf induced in the coil due to its rotation.

Answer 1

Given:

$\Delta \theta=\pi/3$

$\Delta t=0.2\:\rm s$

$N=40$

$A=200*10^{-4}\:\rm m^2$

$B=2\:\rm T$

The magnitude of the EMF induced in the coil

$${\cal E}=NBA\omega=NBA\frac{\Delta \theta}{\Delta t}$$

$${\cal E}=40*2*200*10^{-4}*\frac{\pi/3}{0.2}=8.4\:\rm V$$