A $140-mH$ inductor and a $4\mathrm{.}80-$ resistor are connected with a switch to a $6\mathrm{.}00-V$ battery as shown in the figure below.

$($i$)$

$($a$)$ After the switch is first thrown to a $($connecting the battery$),$ what time interval elapses before the current reaches $220mA?$

$ms$

$($b$)$ What is the current in the inductor $10\mathrm{.}0s$ after the switch is closed?

A

$($c$)$ Now the switch is quickly thrown from $a$ to $b.$ What time interval elapses before the current in the inductor falls to $160mA?$

$ms$