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Chapter 30: Q. 35 (page 871)

At , the current in thet=0scircuit in FIGURE EX30.35is I0. At what time is the current 12I0

Short Answer

Expert verified

Time for current12I0is173μs.

Step by step solution

01

Formula for current and time constant

Current decays across the inductor in a LRcircuit.

I=Ioe-t/τ

localid="1648833013057" τis a constant in time.

Furthermore, the temporal constant is given by

τ=LR

02

Calculation for time for current12I0

As it stands,

Req=300Ω

L=75×10-3H

all values should be substituted,

τ=LR=75×10-3300Ω

I=Io2Then,

I=Ioe-t/τ

Io2=Ioe-t/250μs

ln0.5=-t250μs

t=173μs

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