Two different coils have self inductance $L_1=8 \mathrm{mH}$ and $L_2=2 \mathrm{mH}.$ The current in one coil is increased at a constant rate. The current in the second coil is also increased at the same rate. At a certain instant of time. power given to both the coils is the same. At the time, the current, the induced voltage and the energy stored in the first coil are $i_1,v_1$ and $W_1$ respectively. Corresponding values for the second coil at the same instant are $i_2, v_2$ and $W_2$ respectively. Then find the value of $\frac{W_2}{W_1}=$

The coupling coefficient of the perfectly coupled coil is:

Current in a coil with self-inductance $2 \mathrm{H}$ is increasing according to$I=\left(2{\mathrm{sint}}^2\right)$ ampere. Amount of energy spent during the period when current changes from $0$ to $2 \mathrm{A}$ is $\underline{ }$

Find the equivalent inductance between $A$ and $B$ in the given circuit.

Alternating Current cannot be used for which of the following ?

The figure shows an LCR network connected to a $300 \mathrm{V}$ $AC$ supply. The circuit elements are such that $R=X_L=$ $X_C=10\mathrm{\Omega }.$ Three voltmeters $V_1, V_2$ and $V_3$ are connected as shown. Which of the following represents the correct set of readings of the voltmeters?