The inductance of a solenoid $0.5 \, m$ long of cross-sectional area $20 \, cm^2$ and with $500$ turns is......$mH$

The self-inductance of a circuit is numerically equal to

Physically,the self-inductance plays the role of

The unit of self-inductance is:

The current in a coil changes from $2 \,A$ to $5 \,A$ in $0.3 \,s$. The magnitude of emf induced in the coil is $1.0 \,V$. The value of self-inductance of the coil is (in $\,mH$)

Two different coils have self-inductance $3L$ and $L$. The current in both the coils is increased at the same constant rate. At a certain instant of time, the power given to the two coils is same. At that time, there was current and voltage induced in the two coils. At the same instant, the ratio of energy stored in the first coil to that in the second coil is