Question:
A solenoid having inductance $4.0 \mathrm{H}$ and resistance $10 \Omega$ is connected to a $4.0 \mathrm{~V}$ battery at $\mathrm{t}=0$. Find
(a) the time constant,
(b) the time elapsed before the current reaches $0.63$ of its steady-state value,
(c) the power delivered by the battery at this instant and
(d) the power dissipated in Joule heating at this instant.
Solution: