(13%) Problem 7: A 1.7 H inductor in an RL circuit (with resistance 1.9 ) is ini
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Question
(13%) Problem 7: A 1.7 H inductor in an RL circuit (with resistance 1.9 ) is initially fully charged. A switch is then thrown (between positions 1 and 2, see figure), which causes the inductor to discharge. The initial current through this discharging circuit is 5.2 A Randomized Variables 2 I 5.2 A L=1.7H R=1.9 Otheexpert 33% Part (a) What is the initial energy in the inductor in J? 33% Part (b) How long will it take the current to decline to 25.00% of its initial value? Express this value in seconds Grade Summ Deductions Potential sin() cos cotan asin) acos0 Submissions Attempts rema (4% per attem detailed view tan sinh) atan)acotan) cosh)tanh) cotanh0 0 Degrees Radians Submit Hint I give up! Hints: 0% deduction per hint. Hints remaining: 3 Feedback: 0% deduction per feedback. 33% Part (c) Calculate the average power dissipated in W All content © 2018 Expert TA, LLCExplanation / Answer
a)
Initial energy in the inductor
Einitial=(1/2)LIo2=(1/2)*1.7*5.22=22.984 J
b)
In a RL circuit Current as a function of time is Given by
I=Ioe-t/T
Time Constant
T=L/R =1.7/1.9 =0.8947 s
=>0.25Io=Ioe-t/0.8947
Ln(0.25) =-t/0.8947
t=1.24 s
c)
Average power dissipated
Pav=I2R =5.22*1.9 =51.4 Watts
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