$A$ bar magnet falls from rest under gravity through the centre of a horizontal ring of conducting wire as shown in figure. Which of the following graph best represents the speed $(v)$ vs. time $(t)$ graph of the bar magnet?

$STATEMENT-1$ $A$ 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.

The figure shows a part of a complete circuit. The potential difference $V_B - V_A$ when the current $I$ is $5 \ A$ and is decreasing at a rate of $10^3 \ A \ s^{-1}$ is given by ........ $V$.

$A$ short magnet is allowed to fall along the axis of a horizontal metallic ring. Starting from rest,the distance fallen by the magnet in one second may be.....$m$

In a coil of resistance $100 \ \Omega$,a current is induced by changing the magnetic flux through it as shown in the figure. The magnitude of change in flux through the coil is......$Wb$.

In the figure,the switch $S$ is closed so that a current flows in the iron-core inductor which has inductance $L$ and the resistance $R$. When the switch is opened,a spark is obtained at the contacts. The spark is due to