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An inductor of 10 \mathrm{mH} is connected to a 20 \mathrm{~V} battery through a resistor of 10 \mathrm{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 \mathrm{s} is \frac{\mathrm{x}}{100} \mathrm{~mA}. Then \mathrm{x} is equal to _______. \left(\right. Take\, \, \mathrm{e}^{-1}=0.37 )
 

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L= 10\times 10^{-3}H
R= 10k\Omega = 10^{4}\Omega

After a long time \left ( t\rightarrow \infty \right ),Current\, in \, the \, circuit = I_{0}= \frac{V}{R}= 2\times 10^{-3}A
(\because Inductor will behave as short  ckt or straight conducting wire)
As the switch is opened, there will be a decay of current
I_{t}= I_{0}\, e^{\frac{-t}{t}}
t= \frac{L}{R}= \frac{10^{-2}}{10^{4}}= 10^{-6}
at t= 10^{-6}s
I_{t}= I_{0}\, e^{-1}
    = 2\times 10^{-3}\times 0\cdot 37
   = 0\cdot 74\times 10^{-3}A
I_{t}= \frac{74}{100}mA
\therefore X= 74

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vishal kumar

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