When current in a coil changes from $5\,A$ to $2\,A$ in $0.1\,s,$ an average voltage of $50\,V$ is produced. The self-inductance of the coil is.......$H$.

In a coil of self-inductance $0.5 \, H$,the current varies at a constant rate from $0 \, A$ to $10 \, A$ in $2 \, s$. The $e.m.f.$ generated in the coil is ... $V$.

$A$ coil is wound as a transformer of rectangular cross-section. If all the linear dimensions of the transformer are increased by a factor of $2$ and the number of turns per unit length of the coil remains the same,the self-inductance increases by a factor of:

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:

$A$ toroid is a long coil of wire ($N$ turns) wound over a circular core. The coefficient of self-induction of the toroid is [The magnetic field in it is uniform and $R >> r$,where $r=$ radius of wire,$R=$ radius of coil] ($\mu_0=$ permeability of free space).

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 $10^3$?