The magnetic potential energy stored in a certain inductor is $25\, mJ,$ when the current in the inductor is $60\, mA.$ This inductor is of inductance ......$H$.

The magnetic potential energy stored in a certain inductor is $49 \ mJ$ when the current in the inductor is $70 \ mA$. The inductance of the inductor is (in $H$)

$A$ coil of resistance $5 \Omega$ and inductance $4 H$ is connected to a $10 \ V$ battery. The energy stored in the coil is: (in $J$)

The energy stored in a $50 \, mH$ inductor carrying a current of $4 \, A$ will be $J$.

Which of the following statements are correct?
$(a)$ An inductor stores energy in the form of a magnetic field.
$(b)$ $A$ capacitor stores energy in the form of an electric field.
$(c)$ An inductor stores energy in the form of both electric and magnetic fields.
$(d)$ $A$ capacitor stores energy in the form of both electric and magnetic fields.

$(a)$ Obtain the expression for the magnetic energy stored in a solenoid in terms of magnetic field $B$,area $A$,and length $l$ of the solenoid.
$(b)$ How does this magnetic energy compare with the electrostatic energy stored in a capacitor?