The ratio of time constants during growth and decay of current in the circuit is

$A$ constant voltage of $25 \, V$ is applied to a series $L-R$ circuit at $t=0$ by closing a switch. What is the potential difference across the resistor and the inductor at time $t=0$?

$A$ coil has an inductance of $2.5\,H$ and a resistance of $0.5\,\Omega$. If the coil is suddenly connected across a $6.0\,V$ battery,then the time required for the current to rise to $0.63$ of its final value is.....$s$.

The total heat produced in resistor $R$ in an $RL$ circuit when the current in the inductor decreases from $I_0$ to $0$ is

When a certain circuit consisting of an emf $E$,an inductance $L$,and a resistance $R$ is closed,the current in it increases with time according to curve $1$. After one parameter ($L$ or $R$) is changed,the increase in the current follows curve $2$,when the circuit is closed a second time. Which parameter was changed?

$A$ $50 \, V$ potential difference is suddenly applied to a coil with $L = 5 \times 10^{-3} \, H$ and $R = 180 \, \Omega$. The rate of increase of current after $0.001 \, s$ is ....... $A/s$.