$A$ graph of magnetic flux $(\Phi)$ versus current $(I)$ is shown for four inductors $A, B, C, D$. The smallest value of self-inductance is for inductor:

$A$ $12\,V$ battery connected to a coil of resistance $6\,\Omega$ through a switch,drives a constant current in the circuit. The switch is opened in $1\,ms$. The emf induced across the coil is $20\,V$. The inductance of the coil is ........... $mH$.

What length of a very thin wire is required to obtain a solenoid of length $l_0$ and inductance $L$?

When current $I$ passes through an inductor having self-inductance of $4 \ H$. If the current is made double,what will be the new self-inductance of the inductor?

For a solenoid,keeping the turn density constant,if its length is halved and its cross-sectional radius is doubled,then the inductance of the solenoid increases by.....$\%$

In a circular conducting coil,when current increases from $2 \,A$ to $18 \,A$ in $0.05 \,s$,the induced $e.m.f.$ is $20 \,V$. The self-inductance of the coil is.....$mH$.