1. Average power is also called?
a) apparent power
b) reactive power
c) true power
d) instantaneous power
Explanation: 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
2. 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
Explanation: 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
3.The expression of apparent power (Papp) is?
a) VmIm
b) VmIeff
c) VeffIeff
d) VeffIm
Explanation: 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.
4. The power factor=?
a) sinθ
b) cosθ
c) tanθ
d) secθ
Explanation: The expression of power factor is power factor= cosθ. As the phase angle between the voltage and the current increases the power factor decreases.
5. The power factor is the ratio of ________ power to the ______ power.
a) average, apparent
b) apparent, reactive
c) reactive, average
d) apparent, average
Explanation: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
6. . The reactive power equation (Pr) is?
a) Ieff2 (ωL)sin2(ωt+θ)
b) Ieff2 (ωL)cos2(ωt+θ)
c) Ieff2 (ωL)sin(ωt+θ)
d) Ieff2 (ωL)cos(ωt+θ)
Explanation: If we consider a circuit consisting of a pure inductor, the power in the inductor is reactive power and the reactive power equation (Pr) is Pr =Ieff2 (ωL)sin2(ωt+θ)
7. Reactive power is expressed in?
a) Watts (W)
b) Volt Amperes Reactive (VAR)
c) Volt Ampere (VA)
d) No units
Explanation: Reactive power is expressed in Volt Amperes Reactive (VAR) and power is expressed in watts and apparent power is expressed in Volt Ampere (VA).
8. The expression of reactive power (Pr) is?
a) VeffImsinθ
b) VmImsinθ
c) VeffIeffsinθ
d) VmIeffsinθ
Explanation:The expression of reactive power (Pr) is VeffIeffsinθ Volt Amperes Reactive (VAR). Reactive power = VeffIeffsinθ Volt Amperes Reactive (VAR)
9. The power factor is the ratio of ________ power to the ______ power.
a) average, apparent
b) apparent, reactive
c) reactive, average
d) apparent, average
Explanation: The power factor is the ratio of average power to the apparent power. Power factor = (average power)/(apparent power).
10. The expression of true power (Ptrue) is?
a) Pasinθ
b) Pacosθ
c) Patanθ
d) Pasecθ
Explanation: True power is the product of the apparent power and cosθ. The expression of true power (Ptrue) is Pacosθ. True power = Pacosθ