Question

The current $(I)$ in the inductance is varying with time according to the plot shown in figure. Which one of the following is the correct variation of voltage with time in the coil?

• A.
• B.
• C.
• D.

Answer 1

Answer: (D)

$V=-L(di/dt),V$ is proportional to the slope of the $i-t$ graph, which is constant and positive for the first half $(0$ to $T/2)$ and negative and constant for the second half $(T/2$ to $T$ ).
$|V|=L(di/dt)$ in this case.
For first half $V$ is -ve and for the second half it is + ve.