In the diagram shown,if a bar magnet is moved along the common axis of two single-turn coils $A$ and $B$ in the direction of the arrow,what happens to the induced current?

An aluminium ring $B$ faces an electromagnet $A$. The current $I$ through $A$ can be altered.

Out of the following,which law obeys the law of conservation of energy?

The magnitude of flux linked with a coil varies with time as $\phi = 3t^2 + 4t + 7$. The magnitude of the induced e.m.f. at $t = 2 \ s$ is: (in $V$)

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.

If a copper ring is moved quickly towards the south pole of a powerful stationary bar magnet,then: