$A$ coil of self-inductance $10\,mH$ and resistance $0.1\,\Omega$ is connected through a switch to a battery of internal resistance $0.9\,\Omega$. After the switch is closed,the time taken for the current to attain $80\%$ of its saturation value is: [take $ln\,5 = 1.6$] (in $,s$)

An inductor of $10\, \text{mH}$ is connected to a $20\, \text{V}$ battery through a resistor of $10\, \text{k}\Omega$ and a switch. After a long time,when maximum current is set up in the circuit,the current is switched off. The current in the circuit after $1\, \mu\text{s}$ is $\frac{x}{100}\, \text{mA}$. Then $x$ is equal to ...... . (Take $e^{-1} = 0.37$)

Switch $S$ of the circuit shown in the figure is closed at $t = 0$. If $e$ denotes the induced $emf$ in $L$ and $i$ the current flowing through the circuit at time $t$,which of the following graphs is correct?

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 an $LR$ circuit,the time constant is the time in which the current grows from zero to the value (where ${I_0}$ is the steady-state current):

An induction coil stores $32 \ J$ of magnetic energy and dissipates energy as heat at the rate of $320 \ W$ when a current of $4 \ A$ is passed through it. Find the time constant of the circuit when the coil is joined across a battery.