$A$ 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 $mH$)

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

The self-inductance of an air-cored solenoid of length $40 \ cm$,diameter $7 \ cm$ having $200$ turns is nearly: (in $\mu H$)

An inductor is connected to a direct voltage source through a switch. Which of the following statements is true regarding the induced electromotive force $(emf)$?

The network shown in the figure is a part of a circuit. (The battery has negligible internal resistance). At a certain instant,the current is $2 \ A$ and it is decreasing at the rate of $10^2 \ A \ s^{-1}$. What is the potential difference between the points $B$ and $A$ (in $V$)?

Two coils have self-inductance $L_1 = 4 \, mH$ and $L_2 = 1 \, mH$ respectively. The currents in the two coils are increased at the same rate. At a certain instant of time,both coils are given the same power. If $I_1$ and $I_2$ are the currents in the two coils at that instant of time respectively,then the value of $\frac{I_1}{I_2}$ is: