Share
A 2μF capacitor holds a charge of 24μC. The capacitor is discharged through a 3Ω resistor. What is the voltage across the capacitor at the t
Question
A 2μF capacitor holds a charge of 24μC. The capacitor is discharged through a 3Ω resistor. What is the voltage across the capacitor at the time that the current through the resistor is 3A?
a. VC = 9V
b. VC = 8V
c. VC = 12V
d. VC = 3V
in progress
0
Physics
7 months
2021-07-29T20:26:43+00:00
2021-07-29T20:26:43+00:00 2 Answers
3 views
0
Answers ( )
Answer:
The voltage drop across the capacitor is 3V
(d) VC = 3V
Explanation:
Given;
capacitance of the capacitor, C = 2μF
charge of the capacitor, Q = 24μC
resistance of the resistor, R = 3Ω
current through the resistor, I = 3 A
Initial voltage across the capacitor, V₀:
VC₀ = Q/C = 24μ / 2μ = 12 V
voltage across the resistor:
Voltage drop across the capacitor at the time that the current through the resistor is 3A:
VC = VC₀ –
VC = 12V – 9V
VC = 3V
Therefore, the voltage drop across the capacitor is 3V
(d) VC = 3V
Answer:
d. VC = 3V
Explanation:
If a 2μF capacitor holds a charge of 24μC, the voltage across the capacitor initially Vc is expressed as;
Vc = Q/C {since Q = CV}
Vc = 24μC/2μF
Vc = 12Volts
The voltage across the resistor is derived according to ohm’s law;
VR = IR
Given R = 3Ω and I = 3A
VR = 3×3
VR = 9V
If the capacitor is discharged through the resistor, the voltage across the capacitor at the time that the current through the resistor is 3A is expressed as;
VC = Vc – VR
Vc is the voltage across the capacitor during discharging.
VC = 12-9
VC = 3V