Consider a series RC circuit at the left where C- 6 F, R-2 and -20 V. You close
ID: 779273 • Letter: C
Question
Consider a series RC circuit at the left where C- 6 F, R-2 and -20 V. You close the switch at t -0. Find (a) the time constant for theE circuit, (b) the half-life of the circuit, (c) the current at t 0, (d) the voltage across the capacitor att 0, and (e) the voltage across the resistor after a very long time. Given the circuit at the right in which the following values are used: R1 5 RI R2 V. You close the switch at t 0. Find (a) the current through R2 at t-0, and (b) the voltage across R1 after a long time.Explanation / Answer
1)
a) Time constant of the ckt, T = R*C
= 2*10^6*6*10^-6
= 12 s
b) I = Imax*e^(-t/T)
0.5*Imax = Imax*e^(-t1/2/T)
ln(0.5) = -(t1/2)/T
==> t1/2 = -T*ln(0.5)
= -12*ln(0.5)
= 8.32 s
c) at t = 0, I = 0
d) at t = 0, V_C = V_battery
= 20 V
e) after a long time, V_R = 0
because, the poetetial drops at resistor.