For the circuit diagram as Figure 4 of Assignment 7 epsilon = 15 kV; R = 4.5 k O
ID: 1456037 • Letter: F
Question
For the circuit diagram as Figure 4 of Assignment 7 epsilon = 15 kV; R = 4.5 k Ohm, and C = 7800.0 mu F Determine the time constant for the circuit. 3.51 Times 10^(1) s. 2.58 Times^(-1) s 1.61 Times 10^(-3)s 7.51 Times 10^(-6)s 1.54 Times 10^(2) Determine the maximum charge that will appear on the capacitor 1.51 Times 10^(-2)C 2.58 Times 10^(-5)C 2.61 Times 10^(2) C 7.51 Times 10^(-9) C 1.17 Times 10^(2) C Assuming that the capacitor in initially uncharged, how will it take for the capacitor to charge to half the maximum charge? 1.51 Times 10^(-1)s 35.8 s 24.3 s 7.51 Times 10^(-2)s 15.4sExplanation / Answer
A.
time constant is given by
tau = RC = 4.5*10^3*7800*10^-6 = 35.1 sec
Option A.
B.
maximum charge is given by
Q0 = C0*V0 = 7800*10^-6*15*10^3 = 117 C
Option E.
C.
relation between Q and t ia given by
Q = Q0*(1 - e^(-t/tau))
Q = Q0/2
Q0/2 = Q0*(1 - e^(-t/tau))
e^(-t/tau) = 1/2
-t/tau = ln (1/2)
t = tau*ln 2
t = 35.1*ln 2 = 24.33 sec
Option C.