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.....$mH$.

In the given circuit, if $\frac{dI}{dt} = -1 \, A/s$, then the value of $(V_A - V_B)$ at this instance will be (in $\, V$)

Two solenoids have identical geometrical construction and the same number of turns,but one is made of thick wire and the other of thin wire. Which of the following quantities are different for the two solenoids?
$(a)$ Self-inductance.
$(b)$ Rate of Joule heating if the same current flows through them.
$(c)$ Magnetic potential energy if the same current flows through them.
$(d)$ Time constant.

$A$ long solenoid has $1500$ turns. When a current of $3.5 \, A$ flows through it, the magnetic flux linked with each turn of the solenoid is $2.8 \times 10^{-3} \, Wb$. The self-inductance of the solenoid is (in $ \, H$)

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 . . . . . . $H$.

The magnitude of the induced emf in a coil of inductance $30 \ mH$ in which the current changes from $6 \ A$ to $2 \ A$ in $2 \ s$ is: (in $V$)