Calculating Charge and Time in a Discharging RC Circuit

[Moolisa]

Homework Statement

RC circuit, with a resistor, capacitor and a switch with
ΔV_C =80V R=1.5MΩ C=22μF
The switch is initially open. The switch is closed at t=0
(a) What is the charge in the capacitor when the current is 33μA
(b) How times does it take for the current to reach 33μA
2. The attempt at a solution
(a) So I think the capacitor is discharching.
Since ΔV_C -IR=0, and ΔV_C=Q/C is the charge when I=33μA
Q=IRC?
(b) If part (a) is correct, can I use Q=Q₀ e^-t/RC and find the time from there?

 

[Charles Link]

It looks correct to me. For part b, how do you compute $Q_o$? I don't think you showed that.

 

[Moolisa]

It looks correct to me. For part b, how do you compute $Q_o$? I don't think you showed that.

Is it C(80V)?

 

[CWatters]

I'd like to see the circuit.