The megnetic flux through a coil is `5 xx 10^(-4)` Wb. At time t=0. it reduces to ten percent of its original value in 0.5 s. The magnitude of e.m.f. induced in the coil is

Options

A. 0.9 mV
B. 0.45 mV
C. 2 mV
D. 5 mV

Answer

A

Explanation

`e = (d phi)/(dt)=9/10 xx (5 xx 10^(-4))/(0.5) = 0.9 mV`