What is the self-inductance of a coil which produces a self-induced $EMF$ of $5 \ V$ when the current changes from $3 \ A$ to $2 \ A$ in $1 \ ms$?

The current through an inductor is given by $i = (10 + 20t) \, A$,where $t$ is in $s$. The induced $emf$ in the inductor is $4 \, V$. The total flux linked with the inductor at $t = 2 \, s$ is ...... $Wb$.

When the current through a solenoid increases at a constant rate, the induced current

Two identical inductors carry currents that vary with time according to linear laws (as shown in the figure). In which of the two inductors is the self-induced $emf$ greater?

Why is self-induced $emf$ known as back $emf$?

The current in a coil decreases from $1 \, A$ to $0.2 \, A$ in $10 \, s$. Calculate the coefficient of self-inductance if the induced $e.m.f.$ is $0.4 \, V$. (in $, H$)