The Figure Shows a Circuit $\varepsilon = 27 \mathrm {~V}$ , the Inductance Is

Short Answer

The figure shows a circuit. The ideal battery has a constant terminal voltage of $\varepsilon = 27 \mathrm {~V}$ , the inductance is $L = 0.40 \mathrm { H }$ , and the resistances are $R _ { 1 } = 12 \Omega$ and $R _ { 2 } = 9.0 \Omega$ . Initially the switch $\mathrm { S }$ is open with no currents flowing. Then the switch is suddenly closed.
(a) What is the current in the resistor $R _ { 1 }$ the instant after the switch is closed?
(b) After leaving the switch has been closed for a very long time, it is opened again. Just after it is opened, what is the current in $R _ { 1 }$ ?