If a coil is open,then its self-inductance $L$ and resistance $R$ become:

The self-inductance of a solenoid is:

Current in a circuit falls from $5.0 \ A$ to $0.00 \ A$ in $0.1 \ s$. If an average emf of $200 \ V$ is induced,then the self-inductance of the circuit is . . . . . . $H$.

Consider a long solenoid of length $l$ and radius $r$. If $n$ is the number of turns per unit length and $\mu_0$ is the permeability of free space, the inductance of the solenoid is:

The current through a choke coil increases from zero to $6 \ A$ in $0.3 \ s$ and an induced $e.m.f.$ of $30 \ V$ is produced. The inductance of the choke coil is ....... $H$.

An air-cored solenoid with $30 \ cm$ length,area of cross-section $25 \ cm^2$,and $500$ turns carries a current of $2.5 \ A$. The current is suddenly switched off in a brief time of $10^{-3} \ s$. How much is the average back emf induced across the ends of the open switch in the circuit (in $V$)? (Ignore the variation in magnetic field near the ends of the solenoid.)