When the current changes from $+2 \, A$ to $-2 \, A$ in $0.05 \, s$,an $e.m.f.$ of $8 \, V$ is induced in a coil. The coefficient of self-induction of the coil is ... $H$.

Current in a circuit falls from $5.0 \ A$ to $0.0 \ A$ in $0.1 \ s$. If an average emf of $100 \ V$ is induced,then the value of self-inductance of the circuit is . . . . . . . (in $H$)

When the number of turns in a coil is doubled without any change in the length of the coil,its self-inductance becomes

The following figure represents two bulbs $B_1$ and $B_2$, a resistor $R$, and an inductor $L$. When the switch $S$ is turned off, which of the following statements is true?

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.

The current in a coil of inductance $0.2 \,H$ changes from $5 \,A$ to $2 \,A$ in $0.5 \,s$. The magnitude of the average induced emf in the coil is (in $\,V$)