Question

012 10.0 points Consider an RC circuit. The energy equa- tion for the circuit is given by AVround trip =-RI – 8 = 0 (see textbook p813). Based on this equation it can be shown, by using 1 = 2, that Q(t) = Qo exp ( - ), where T = RC. Given that C = 0.02 uF, and the initial plate charge is Qo. After 9 s, the plate charge is 0.5Qo. What is the resistance of the resistor across the capacitor.? Answer in units of MS.

Answer 1

This problem requires simple substitution into the derived equation to find the answer. We are being asked to find the resistance of the across the capacitor after $9\mathrm{s}$ . We know that the charge at that time is $0.5Q_0$ .

Q=Qoe-

We know that

T= RC

Substituting this,

Q=Qoe RC

At

t=9s

Qoe RX0.024F = 0.500

e RX0.02F = 0,5

RX 0.02F=-0.693

Solving for , we get

R = 649.35ΜΩ