Two identical conducting rings $A$ and $B$ of radius $R$ are in pure rolling over a horizontal conducting plane with the same speed (of centre of mass) $u$ but in opposite direction. A constant magnetic field $B$ is present pointing inside the plane of the paper. Then the potential difference between the highest points of the two rings is :

In the circuit shown in figure, the switch $S$ was initially at position $1$. After a sufficiently long time, the switch $S$ was thrown from position $1$ to position $2$.

The voltage drop across the resistor at that instant is :

As shown in the figure, the key $K$ is closed, the direction of the induced current in the coil $B$ will be-

A copper ring is tied to a string and suspended vertically. On bringing a magnet towards the coil, as shown in the figure -

The graph between the current and the time for an inductance coil is shown below. Which of the following graph show the voltage-time variation?

A metallic square loop $ABCD$ is moving in its own plane with velocity $v$ in a uniform magnetic field perpendicular to its plane as shown in the figure. An electric field is induced -

$P$ and $Q$ are two circular thin coils of the same radius and subjected to the same rate of change of flux. If coil $P$ is made up of copper and $Q$ is made up of iron, then the wrong statement is