A vertical rod of length $l$ is moved with constant velocity $v$ towards east. The vertical component of the earth's magnetic field is $B$ and the angle of dip is $\mathrm{\theta }$. The induced $\mathrm{e}.\mathrm{m}.\mathrm{f}.$ in the rod is,

A constant force $F$ is being applied on a rod of length $l$ kept at rest on two parallel conducting rails connected at ends by resistance $R$ in uniform magnetic field $B$ as shown,

Figure shows a square loop of side $1 \mathrm{m}$ and resistance $1 \mathrm{\Omega }$. The magnetic field on left side of line $PQ$ has a magnitude $B=1.0 \mathrm{T}$. The work done in pulling the loop out of the field uniformly in $1 \mathrm{s}$ is,

$A$ and $B$ are two metallic rings placed at opposite sides of an infinitely long straight conducting wire as shown. If current in the wire is slowly decreased, the direction of induced current will be,

A vertical conducting ring of radius $R$ falls vertically with a speed $V$ in a horizontal uniform magnetic field $B$ which is perpendicular to the plane of the ring.

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 :