A circular coil of radius 10 cm, 500 turns and resistance 2`Omega` is placed with its plane, perpendicular to the horizontal component of the earth's magnetic field. It is rotated about its vertical diameter through `180^@` in 0.25 s. The induced e.m.f. in the coil is ..... (Take `H_E=3.0xx10^(-5)` T)

Options

A. `6.6xx10^(-4)` V
B. `1.4xx10^(-2)` V
C. `2.6xx10^(-2)` V
D. `3.8xx10^(-3)` V

Answer

D

Explanation

`Deltaphi=NAB cos 180^@ - NAB cos 0^@`
=NAB(-1)-NAB
=-2NAB
`epsilon=-(Deltaphi)/(Deltat)`
`=(2NAB)/(Deltat)`
`=(2xx500xx3.14xx(10xx10^(-2))^2 xx 3xx10^(-5))/0.25`
`=(1000xx3.14xx10^(-2)xx3xx10^(-5))/(25xx10^(-2))`
`=376.8xx10^(-5) approx 3.8xx10^(-3)` V