The current $I$ in an $A.C.$ circuit inductance coil varies with time according to the graph given below. Which one of the following graphs gives the variation of voltage with time?

$STATEMENT-1$ $A$ vertical iron rod has a coil of wire wound over it at the bottom end. An alternating current flows in the coil. The rod goes through a conducting ring as shown in the figure. The ring can float at a certain height above the coil. Because
$STATEMENT-2$ In the above situation,a current is induced in the ring which interacts with the radial component of the magnetic field to produce an average force in the upward direction.

In the given circuit,when does the lamp become momentarily bright?

The diagram below shows two coils $A$ and $B$ placed parallel to each other at a very small distance. Coil $A$ is connected to an ac supply. $G$ is a very sensitive galvanometer. When the key $K$ is closed:

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 $L_2$):-

$A$ coil having $N$ turns and resistance $R$ $\Omega$ is connected to a galvanometer of resistance $6R$ $\Omega$. The magnetic flux linked with this coil changes from $\phi_1$ weber to $\phi_2$ weber in time $t$ second. The induced current in the circuit is