$A$ coil of resistance $10 \, \Omega$ and an inductance $5 \, H$ is connected to a $100 \, V$ battery. The energy stored in the coil is:

If the current in a coil is halved,then the energy stored becomes how many times the previous value?

Assertion : If the current in a solenoid is reversed in direction while keeping the same magnitude,the magnetic field energy stored in the solenoid remains unchanged.
Reason : Magnetic field energy density is proportional to the magnetic field.

$A$ coil of inductance $2\, H$ having negligible resistance is connected to a source of supply whose voltage is given by $V = 3t$ volt (where $t$ is in seconds). If the voltage is applied when $t = 0$,then the energy stored in the coil after $4\, s$ is ............ $J$.

Two circuits $A$ and $B$ are connected to identical d.c. sources each of e.m.f. $10 \ V$. Self-inductances of circuits $A$ and $B$ are respectively $L_A = 10 \ H$ and $L_B = 10 \ mH$. The total resistance of each circuit is $40 \ \Omega$. The ratio of energy consumed in circuit $A$ and circuit $B$ to build up the current to steady value is

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 $H$)