33) For circuit shown, let ? =10v. Initially the switch is open and the capacito
ID: 2137999 • Letter: 3
Question
33) For circuit shown, let ?=10v. Initially the switch is open and the capacitor is uncharged. When the switch is closed, there is an initial instantaneous current of 1.00 mA in the resistor. Two seconds later the current through the resistor has fallen to .37mA. What are the values of R and C?
Explanation / Answer
given Io=1mA =1*10^-3 A
E=10 V
Io=E/R
=>R =10/(1*10^-3)
R =1*10^4 ohms
I=Ioe^(-t/RC)
0.37=1e^(-2/10000C)
-2/10000C =ln(0.37) =-1
C=2*10^-4 F or 200 uF