A $50 \mathrm{mH}$ coil carries a current of $2 \mathrm{A}$, the energy stored in joule is

What is the magnetic induction, If square coil of side $25 \mathrm{cm}$ having $1000$ turns is rotated with a uniform speed is a magnetic field an axis perpendicular to the direction of the field. At an instant $t$. The emf induced in the coil is $e=200\sin 100\pi t$.

A rectangular loop of length $l$ and breadth $b$ is placed at a distance of $x$ from infinitely long wire carrying current $l$ such that the direction of current is parallel to breadth. If the loop moves with a velocity $v$ away from the current wire in a direction perpendicular to it, the magnitude of the emf