Question

An R-L circuit has a 60 V battery, a 42 H inductor, a 24 ohm resistor, and a switch S, in series, as shown. Initially, the switch is open, and there is no magnetic flux in the inductor. At time   the switch is closed. In Figure 21.23b, when the resistor voltage is equal to the inductor voltage, the current in the circuit is closest to:

		1.3 A
		1.0 A
		0.50 A
		1.5 A
		0.75 A

Answer 1

by kirchoof's loop rule we can say

60-Vr-VL= 0

60=Vr+VL

If Vr=VL

60-2Vr=0

60=2Vr

ohm's law say's V=IR

so 60=2*IR

60/2*24=I

1.25amp=I

appx the naswer be 1.3amp

answer is A