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rodikova [14]
2 years ago
4

How many time constants must elapse if an initially charged capacitor is to discharge 90% of its stored energy through a resisto

r
Physics
1 answer:
AleksandrR [38]2 years ago
4 0

Answer:

t = log9/10 x RC

Explanation:

Let's say initial energy is

E= 1/2Q²/C

But if 90% is discharged what will be remaining will be

E= E"/100= 1/2Q²/C

So if we divide the first by the second equation we have

Q'= Q/10

Then using

q=q0(1-e^-t /RC)

So that

Q= Q/10(1-e^-t /RC)

t/RC= log9/10

So t = log9/10 x RC

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Answer:

293.7 degrees

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