An $e.m.f.$ of $15 \ V$ is applied in a circuit containing $5 \ H$ inductance and $10 \ \Omega$ resistance. The ratio of the currents at time $t = \infty$ and at $t = 1 \ s$ is:

In the given $L-R$ circuit,which of the following statements is correct?

In the circuit shown,the key $(K)$ is closed at $t = 0$. Find the current through the key at the instant $t = 10^{-3} \ln 2 \, s$.

An ideal coil of $10 \ H$ is connected in series with a resistance of $5 \ \Omega$ and a battery of $5 \ V$. $2 \ s$ after the connection is made,the current flowing in the circuit in amperes is:

In the figure shown,a circuit contains two identical resistors with resistance $R = 5\,\Omega$ and an inductance with $L = 2\, mH$. An ideal battery of $15\, V$ is connected in the circuit. What will be the current through the battery long after the switch $S$ is closed (in $, A$)?

In the given figure,an inductor of $L = 4 \, H$ and a resistor of $R = 25 \, \Omega$ are connected in series with a battery of emf $E$ volt. $\frac{E^a}{2b} \, J/s$ represents the maximum rate at which energy is stored in the magnetic field of the inductor. The numerical value of $\frac{b}{a}$ is ............