Network Theory Interview Questions and Answers for Experienced people on “Apparent Power and Power Factor”.
1. The highest power factor will be?
A. 1
B. 2
C. 3
D. 4
Answer: A
Clarification: The power factor is useful in determining the useful power transferred to a load. The highest power factor will be 1.
2. If power factor = 1, then the current to the load is ______ with the voltage across it.
A. out of phase
B. in phase
C. 90⁰ out of phase
D. 45⁰ out of phase
Answer: B
Clarification: If power factor = 1, then the current to the load is in phase with the voltage across it because the expression of power factor is power factor = cosθ.
3. In case of resistive load, what is the power factor?
A. 4
B. 3
C. 2
D. 1
Answer: D
Clarification: In case of resistive load, the power factor = 1 as the current to the load is in phase with the voltage across it.
4. If power factor = 0, then the current to a load is ______ with the voltage.
A. in phase
B. out of phase
C. 45⁰ out of phase
D. 90⁰ out of phase
Answer: D
Clarification: If the power factor = 0, then the current to a load is 90⁰ out of phase with the voltage and it happens in case of reactive load.
5. For reactive load, the power factor is equal to?
A. 0
B. 1
C. 2
D. 3
Answer: A
Clarification: For reactive load, the power factor is equal to 0. Power factor = 0 when current to a load is 90⁰ out of phase with the voltage.
6. Average power is also called?
A. apparent power
B. reactive power
C. true power
D. instantaneous power
Answer: C
Clarification: The average power is expressed in watts. It means the useful power transferred from the source to the load, which is also called true power. Average power is also called true power.
7. If we apply a sinusoidal voltage to a circuit, the product of voltage and current is?
A. true power
B. apparent power
C. average power
D. reactive power
Answer: B
Clarification: If we apply a sinusoidal voltage to a circuit, the product of voltage and current is apparent power. The apparent power is expressed in volt amperes or simply VA.
8. The expression of apparent power (Papp) is?
A. VmIm
B. VmIeff
C. VeffIeff
D. VeffIm
Answer: C
Clarification: In case of sinusoidal voltage applied to the circuit, the product of voltage and the current is not the true power or average power and it is apparent power. The expression of apparent power (Papp) is Papp = VeffIeff.
9. The power factor=?
A. sinθ
B. cosθ
C. tanθ
D. secθ
Answer: B
Clarification: The expression of power factor is power factor= cosθ. As the phase angle between the voltage and the current increases the power factor decreases.
10. The power factor is the ratio of ________ power to the ______ power.
A. average, apparent
B. apparent, reactive
C. reactive, average
D. apparent, average
Answer: A
Clarification: The power factor is the ratio of average power to the apparent power. Power factor =(average power)/(apparent power). Power factor is also defined as the factor with which the volt amperes are to be multiplied to get true power in the circuit.
11. The power factor is called leading power factor in case of ____ circuits.
A. LC
B. RC
C. RL
D. RLC
Answer: B
Clarification: The power factor is called leading power factor in case of RC circuits and not in RLC circuits and RL circuits and LC circuits.
12. The term lagging power factor is used in which circuits?
A. RLC
B. RC
C. RL
D. LC
Answer: C
Clarification: The term lagging power factor is used in RL circuits and not in RLC circuits and RC circuits and LC circuits.
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