Two inductor coils of self-inductance $3\,H$ and $6\,H$ respectively are connected with a resistance $10\,\Omega$ and a battery $10\,V$ as shown in the figure. The ratio of the total energy stored at steady state in the inductors to that of the heat developed in the resistance in $10\,s$ at the steady state is (neglect mutual inductance between $L_1$ and $L_2$):-

$A$ conducting square loop initially lies in the $XZ$ plane with its lower edge hinged along the $X$-axis. Only in the region $y \geq 0$,there is a time-dependent magnetic field pointing along the $Z$-direction,$\vec{B}(t) = B_0(\cos \omega t) \hat{k}$,where $B_0$ is a constant. The magnetic field is zero everywhere else. At time $t=0$,the loop starts rotating with constant angular speed $\omega$ about the $X$-axis in the clockwise direction as viewed from the $+X$ axis (as shown in the figure). Ignoring self-inductance of the loop and gravity,which of the following plots correctly represents the induced e.m.f. $(V)$ in the loop as a function of time?

Two circular coils $P$ and $Q$ are fixed coaxially and carry currents $I_1$ and $I_2$ respectively.

$A$ coil is placed in a time-varying magnetic field. If the number of turns in the coil were to be halved and the radius of the wire doubled,the electrical power dissipated due to the current induced in the coil would be: (Assume the coil to be short-circuited.)

$A$ conducting circular loop of resistance $20 \Omega$ and cross-sectional area $20 \times 10^{-2} \,m^{2}$ is placed perpendicular to a spatially uniform magnetic field $B$, which varies with time $t$ as $B = 2 \sin(50 \pi t) \,T$. Find the net charge flowing through the loop in $20 \,ms$ starting from $t = 0$. (in $\,C$)

What length of wire is required to construct a solenoid of length $l_0$ and inductance $L$?