An $e.m.f.$ of $5 \,V$ is produced by a self-inductance when the current changes at a steady rate from $3 \,A$ to $2 \,A$ in $1 \,ms$. The value of self-inductance is:

The self-inductance of a long solenoid of cross-sectional area $A$,length $l$ and $n$ turns per unit length is given by

Physically,the self-inductance plays the role of

What is the self-inductance of a solenoid of length $31.4 \ cm$,area of cross-section $10^{-3} \ m^2$,and total number of turns $10^3$?

An air-cored coil has a self-inductance of $0.1 \ H$. $A$ soft iron core of relative permeability $1000$ is introduced,and the number of turns is reduced to $\frac{1}{10}$ of the original. The new value of self-inductance is:

The average $e.m.f.$ induced in a coil in which a current changes from $0$ to $2 \,A$ in $0.05 \,s$ is $8 \,V.$ The self-inductance of the coil is: