A coil having 200 turns has a surface of 0.15 `m^2`. A magnetic field of strength 0.2 T applied perpendicular to this changes to 0.6 T in 0.4 s. then the induced emf in the coil is …. V.

Options

A. 45
B. 30
C. 15
D. 60

Answer

B

Explanation

`A=0.15 m_2, N=200`
`B_1=0.2 T , B_2=0.6T`
`Deltat`=0.4 s
Magnitude of induced emf
`epsilon=N (Deltavarphi)/(Deltat)`
`=N(AB_2-AB_1)/(Deltat)`
`=NA(B_2-B_1)/(Deltat)`
`=200xx0.15xx(0.6-0.2)/0.4` = 30 V