Single Phase Series Circuit MCQ [Free PDF] – Objective Question Answer for Single Phase Series Circuit Quiz

41. 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

Z = 26Ω, XC = 24Ω

Z2 = R2+XC2

Substituting the values we get,

262  = R2 + 242

676 = R2 + 576

R2  = 100

R = 10 Ω.

 

43. If in an alternating current circuit, a 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

XC = 1/(2πfC)= 106.1

I = V/XC

= 200/106.1 = 1.89 A.

 

44. If in an alternating current circuit, capacitance C is connected to a supply of 200V, 50Hz. The 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

Capacitive Reactance

XC = V/I

= 200/1.89 = 106.1 Ω.

XC = 1/(2πfC).

Substituting the values we get C = 30 µF.

 

45. In an ac circuit, the resistance of 5 ohms is connected with a capacitor having capacitive reactance of 12 ohms. A 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

Z2 = R2+XC2

Substituting the values we get

Z2  = 52 + 122

Z2  = 169

Z = 13 Ω.

I = V/Z = 260/13 = 20 A.

 

46. In an ac circuit, the resistance of 5 ohms is connected with a capacitor having capacitive reactance of 12 ohms. A 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

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.

 

47. In an ac circuit, resistance 5 ohm is connected with a capacitor having capacitive reactance 12 ohm. A 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

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.

 

48. Find the total voltage applied in a series RLC circuit when i = 3mA, VL = 30V, VC = 18V, and R = 1000 ohms.

A. 3.95 V
B. 51 V
C. 32.67 V
D. 6.67 V

Answer: B

Total voltage = VR+VL+VC.

VR = 1000 × 3 × 10-3 = 3V.

Therefore, total voltage = 30+18+3 = 51V.

 

49. In an RLC circuit, which of the following is always used as a vector reference?

A. Voltage
B. Resistance
C. Impedance
D. Current

Answer: A

In an RLC circuit, the voltage is always used as a reference and according to the phase of the voltage, the phase of the other parameters is decided.

 

50. In an RLC circuit, the power factor is always _________

A. Positive
B. Negative
C. Depends on the circuit
D. Zero

Answer: C

In an RLC series circuit, the power factor depends on the number of resistors and inductors in the circuit, hence it depends on the circuit.

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