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(I need help with part C-E, I have already done part A & B) And some help on the

ID: 1536917 • Letter: #

Question

(I need help with part C-E, I have already done part A & B) And some help on the exercise portion. Please write LEGIBLY

(a) the time constant of the circuit
4.785 s

(b) the maximum charge on the capacitor
71.5 µC

(c) the charge on the capacitor after 6.10 s
_____µC

(d) the potential difference across the resistor after 6.10 s
________V

(e) the current in the resistor at that time
_______A

EXERCISE HINTS:  GETTING STARTED | I'M STUCK!

Use the values from PRACTICE IT to help you work this exercise.

(a) Find the charge on the capacitor after 1.90 s have elapsed.
Q =_____ C

(b) Find the magnitude of the potential difference across the capacitor after 1.90 s.
VC = _______V

(c) Find the magnitude of the potential difference across the resistor at that same time.

VR =________ V

Explanation / Answer

c)

charge on the capacitor at any time is given as

Q = Qmax (1 - e-t/T)

Q = (71.5 x 10-6) (1 - e-6.10/4.785)

Q = 0.0000514 C = 51.4 uC

d)

Vc = potential difference across the capacitor after t = 4.785 sec , = Q/C = 51.4/5.5 = 9.4 volts

Vr = resistance across the resistor = E - Vc = 13 - 9.4 = 3.6 volts

e)

current in the resistor is given as

i = Vr/R = 3.6/(8.7 x 105) = 4.13 x 10-6 A

a)

charge on the capacitor at any time is given as

Q = Qmax (1 - e-t/T)

Q = (71.5 x 10-6) (1 - e-1.9/4.785)

Q = 23.4 uC

b)

Vc = potential difference across the capacitor after t = 1.9 sec , = Q/C = 23.4/5.5 = 4.25 volts

c)

Vr = resistance across the resistor = E - Vc = 13 - 4.25 = 8.75 volts