250+ TOP MCQs on Resistance and Capacitance in Series and Answers

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Basic Electrical Engineering Multiple Choice Questions on “Resistance and Capacitance in Series”.

1. If in an alternating current circuit, resistance is 5 ohm, capacitive reactance is 12 ohm, what is the impedance?
A. 5 ohm
B. 10 ohm
C. 12 ohm
D. 13 ohm
Answer: D
Clarification: R=5Ω, XC=12Ω
Z2=R2+XC2 Substituting the values we get,
Z2 = 52 + 122
Z2 = 169
Z=13 Ω.

2. If in an alternating current circuit, impedance is 26 ohm, capacitive reactance is 24 ohm, what is the resistance?
A. 25 ohm
B. 10 ohm
C. 12 ohm
D. 23 ohm
Answer: B
Clarification: Z=26Ω, XC=24Ω
Z2=R2+XC2 Substituting the values we get,
262 = R2 + 242
676 = R2 + 576
R2 = 100
R=10 Ω.

3. If in an alternating current circuit, capacitance of 30 µF is connected to a supply of 200V,50Hz. Find the current in the circuit.
A. 1.38 A
B. 1.89 A
C. 1.74 A
D. 0.89 A
Answer: A
Clarification: XC=1/(2πfC.=106.1
I=V/XC=200/106.1=1.89 A.

4. If in an alternating current circuit, capacitance C is connected to a supply of 200V,50Hz. Current in the circuit is 1.89 A. Find the capacitance C.
A. 30 µF
B. 20 µF
C. 10 µF
D. 15 µF
Answer: A
Clarification: XC= V/I = 200/1.89 = 106.1 Ω. XC=1/(2πfC. Substituting the values we get C = 30 µF.

5. In ac circuit, resistance 5 ohm is connected with capacitor having capacitive reactance 12 ohm. Supply of 260 V is connected to the circuit. Calculate the current in the circuit.
A. 40 A
B. 10 A
C. 20 A
D. 30 A
Answer: C
Clarification: Z2=R2+XC2 Substituting the values we get Z2 = 52 + 122
Z2 = 169
Z=13 Ω.
I=V/Z = 260/13=20 A.

6. In ac circuit, resistance 5 ohm is connected with capacitor having capacitive reactance 12 ohm. Supply of 260 V is connected to the circuit. Calculate the voltage across resistance.
A. 300 V
B. 200 V
C. 240 V
D. 100 V
Answer: D
Clarification: Z2=R2+XC2 Substituting the values we get
Z2 = 52 + 122
Z2 = 169
Z=13 Ω.
I = V/Z = 260/13=20 A.
VR=iR=20*5=100 V.

7. In ac circuit, resistance 5 ohm is connected with a capacitor having capacitive reactance 12 ohm. Supply of 260 V is connected to the circuit. Calculate the voltage across a capacitor.
A. 300 V
B. 200 V
C. 240 V
D. 100 V
Answer: C
Clarification: Z2=R2+XC2 Substituting the values we get
Z2 = 52 + 122
Z2 = 169
Z=13 Ω.
I = V/Z = 260/13=20 A.
VC=iXC=20*12=240 V.