An LR Circuit Contains an Ideal 60-V Battery,a 42-H Inductor

Multiple Choice

An LR circuit contains an ideal 60-V battery,a 42-H inductor having no resistance,a 24-Ω resistor,and a switch S,all in series.Initially,the switch is open and has been open for a very long time.At time t = 0 s,the switch is suddenly closed.How long after closing the switch will the potential difference across the inductor be 24 V?

A) 1.6 s
B) 1.4 s
C) 1.8 s
D) 1.9 s
E) 2.1 s