Consider a current in a circuit falls from $6.0 \,A$ to $1.0 \,A$ in $0.2 \,s$. If an average emf of $150 \,V$ is induced by the circuit,then the self inductance of the circuit is (in $\,H$)

$A$ solenoid with an air core has length $48 \pi \ cm$,area of cross section $12 \ cm^2$ and $1200$ turns. The self-inductance of the solenoid is: (in $mH$)

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

The self-inductance of a coil having $500$ turns is $50\,mH$. The magnetic flux through the cross-sectional area of the coil when the current through it is $8\,mA$ is found to be:

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:

$A$ graph of magnetic flux $(\phi)$ versus current $(I)$ is shown for $4$ different inductors $P, Q, R, S$. The minimum value of inductance is for inductor: