$A$ magnet $NS$ is suspended from a spring and while it oscillates,the magnet moves in and out of the coil $C$. The coil is connected to a galvanometer $G$. Then as the magnet oscillates,

$A$ part of a complete circuit is shown in the figure. At some instant,the value of current $I$ is $1\, A$ and it is decreasing at a rate of $10^{2}\, A s^{-1}$. The value of the potential difference $V_{P} - V_{Q}$ (in volts) at that instant is:

Which of the following is not a unit of permeability?

$A$ solenoid is oriented end-on so that its opening is perpendicular to the circuit containing the two light bulbs as drawn in figure $C_1.$ For figures $C_2$ and $C_3,$ a shorting wire of negligible resistance is added as shown. Assume that the magnetic field from the solenoid,shown coming out of the plane of the page,decreases uniformly with time at the same rate for each circuit. Rank the circuits for the brightness of the bulb labeled $R_1$ from brightest to dimmest.

The current $i$ in an induction coil varies with time $t$ according to the graph shown. Which of the following graphs shows the induced $emf$ $(e)$ in the coil with time?

$A$ square coil $ABCD$ lies in the $x-y$ plane with its centre at the origin. $A$ long straight wire passing through the origin carries a current $i = 2t$ in the negative $z$-direction. The induced current in the coil is