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A coil has 2000 turns and area of 70cm^...

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

A

`8.4V`

B

`84V`

C

`4.2V`

D

`42V`

Text Solution

Verified by Experts

The correct Answer is:
B
By using `e=(-NBA(costheta_(2)-costheta_(1)))/(Deltat)`
`e=-(1000xx2xx10^(-5)xx500xx10^(-4)(cos180^(@)-cos0^(@)))/(=10^(-2))"volt"=10 mV`
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