This set of Basic Electrical Engineering Multiple Choice Questions & Answers (MCQs) focuses 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
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: 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.
Sanfoundry Global Education & Learning Series – Basic Electrical Engineering.
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