Three identical coils $C_1, C_2$ and $C_3$ are placed coaxially. $C_2$ is exactly midway between $C_1$ and $C_3$. $C_1$ carries current $I$ in an anti-clockwise direction, while $C_3$ carries current $I$ in a clockwise direction. An induced current flows through $C_2$ in a clockwise direction when:

Consider a metal ring kept on top of a fixed solenoid (say on a cardboard) as per the figure. The center of the ring coincides with the axis of the solenoid. If the current is suddenly switched on,the metal ring jumps up. Explain.

The diagram below shows two circular loops of wire ($A$ and $B$) centred on and perpendicular to the $X$-axis and oriented with their planes parallel to each other. The $Y$-axis passes vertically through loop $A$ (dashed line). There is a current $I_B$ in loop $B$ as shown in the diagram. Possible actions which we might perform on loop $A$ are:
$(I)$ move $A$ to the right along $X$-axis closer to $B$
$(II)$ move $A$ to the left along $X$-axis away from $B$
$(III)$ as viewed from above,rotate $A$ clockwise about $Y$-axis
$(IV)$ as viewed from above,rotate $A$ anti-clockwise about $Y$-axis
Which of the actions will induce a current in $A$ only in the direction shown?

The north pole of a bar magnet is moved swiftly downward towards a closed coil and then a second time it is raised upwards slowly. The magnitude and direction of the induced currents in the two cases will be of:

$A$ bar magnet is passing through a conducting loop of radius $R$ with velocity $v$. The radius of the bar magnet is such that it just passes through the loop. The induced $e.m.f.$ in the loop can be represented by the approximate curve:

Discuss the contribution of different scientists to electromagnetism. Define electromagnetic induction.