$A$ copper ring having a cut such as not to form a complete loop is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring as shown in figure. The acceleration of the falling magnet is ($g=$ acceleration due to gravity)

$A$ circular loop of wire is in the same plane as an infinitely long wire carrying a constant current $i$. Four possible motions of the loop are marked by $N, E, W$,and $S$ as shown below. $A$ clockwise current is induced in the loop when the loop is pulled towards:

The magnetic flux $\phi$ through a coil varies with time $t$ as shown in the diagram. Which graph best represents the variation of the induced electromotive force (e.m.f.) $E$ in the coil with time $t$?

It is desired to measure the magnitude of the magnetic field between the poles of a powerful loudspeaker magnet. $A$ small flat search coil of area $2 \; cm^{2}$ with $25$ closely wound turns is positioned normal to the field direction and then quickly snatched out of the field region. (Equivalently,one can give it a quick $90^{\circ}$ turn to bring its plane parallel to the field direction). The total charge flown in the coil (measured by a ballistic galvanometer connected to the coil) is $7.5 \; mC$. The combined resistance of the coil and the galvanometer is $0.50 \; \Omega$. Estimate the field strength of the magnet.

$A$ rectangular coil of $20$ turns and an area of cross-section $25 \, cm^2$ has a resistance of $100 \, \Omega$. If a magnetic field which is perpendicular to the plane of the coil changes at the rate of $1000 \, T/s$,the current in the coil is $....... \, A$.

$A$ magnetic field $4 \times 10^{-2} \, T$ acts at right angles to a coil of area $100 \, cm^2$ with $50$ turns. The average e.m.f. induced in the coil is $0.1 \, V$, when it is removed from the field in time '$t$'. The value of '$t$' is