A cylindrical bar magnet is rotated about its axis. A wire is connected from the axis and is made to touch the cylindrical surface through a contact. Then,

There are two coils $A$ and $B$ as shown in figure. $A$ current starts flowing in $B$ as shown, when $A$ is moved towards $B$ and stops when $A$ stops moving. The current in $A$ is counter clockwise. $B$ is kept stationary when $A$ moves. We can infer that

Same as problem 4 except the coil $A$ is made to rotate about a vertical axis (figure). No current flows in $B$ if $A$ is at rest. The current in coil $A$, when the current in $B($ at $t=0)$ is counter-clockwise and the coil $A$ is as shown at this instant, $t=0$, is

The self inductance $L$ of a solenoid of length $l$ and area of cross-section $A$, with a fixed number of turns $N$ increases as

A metal plate is getting heated. It can be because