A coil having an area of 0.4 `m^(2)` and 100 turns is kept perpendicular to a uniform magnetic field of induction of 0.5 `Wb//m^(2)`. The coil is rotated about one of is diameter so as to cut the lines of induction of the magnetic field. The average value of emf induced in the coil if it is rotated through `60^(@)` in 2 seconds will be

Options

A. 5 V
B. 2.5 V
C. 1.5 V
D. 5.5 V

Answer

A

Explanation

`e=(dphi)/(dt)=(phi_(1)-phi_(2))/(dt)`
`=(nABcostheta_(1)-nABcostheta_(2))/(dt)`
`=(100xx0.4xx0.5xx[cos0-cos60])/(2)=5V`