If the number of turns per unit length in a solenoid is tripled,the self-inductance of the solenoid will

The length of thin wire required to manufacture a solenoid of inductance $L$ and length $\ell$ (if cross-sectional diameter is considered much less than its length) 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 . . . . . . $H$.

The average $e.m.f.$ induced in a coil in which a current changes from $0$ to $2 \,A$ in $0.05 \,s$ is $8 \,V.$ The self-inductance of the coil is:

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.

In a coil,the current changes from $-2 \,A$ to $+2 \,A$ in $0.2 \,s$ and induces an emf of $0.1 \,V$. The self-inductance of the coil is: (in $\,mH$)