K K Sharma Solutions for Chapter: Electromagnetic Induction, Exercise 12: Energy Stored in Inductor

The work done by a source to establish a current of $5 \mathrm{A}$, in an inductor coil of $L=0.04 \mathrm{H}$, is

A time-varying voltage $V=2t \mathrm{volt}$ is applied across an ideal inductor of inductance $L=2 \mathrm{H}$, as shown in the figure. Select the incorrect statement.

Two different coils have self inductance $L_1=8 \mathrm{mH}$ and $L_2=2 \mathrm{mH}$, respectively. The current in one coil is increased at a constant rate and the current in the second coil is also increased at the same constant rate. At a certain instant of time, the power given to the two coils is same. At that time, the current, the induced voltage and the energy stored in the first coil are $i_1, V_1$ and $W_1$, respectively. The corresponding values for the second coil, at the same instant, are $i_2, V_2$ and $W_2$, respectively. Now, select the incorrect option.

A solenoid of $10 \mathrm{H}$ inductance and $2 \mathrm{\Omega }$ resistance is connected to a $10 \mathrm{V}$ battery. In how much time the magnetic energy will increase to one-fourth of its maximum value?

The current in an inductor is given by, $i=\left(2+3t\right) \mathrm{A}$, where $t$ is in seconds. The self-induced emf in it is $9 \mathrm{mV}$. The energy stored in the inductor at $t=1 \mathrm{s}$ is