Question

What is the potential difference between $V_{cd}$ across the inductor $L$ in volts?

Answer 1

When the switch is closed at $t=0$, there will be no current in section $acdb$.

And potential across this section equals $E=120V$

Hence, potential across resistor is $0$.

Hence , potential across inductor is equal to $E$.

$V_{acdb}=V_{ac}+V_{cd}$

$⟹E=0+V_{cd}$

Hence, $V_{cd}=120V$