Q. A solenoid has an inductance of $60\ henry$ and a resistance of $30\ ohms$. If it is connected to a 100 volt battery, how long will it take for the current to reach $\frac{e - 1}{e} \approx 63.2\%$ of its final value
A) $1\ second$
B) $2\ seconds$
C) $e\ seconds$
D) $2e\ seconds$
Explanation
(b) $t = \tau = \frac{L}{R} = \frac{60}{30} = 2\ \sec$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.