Power MCQs : Here you will find MCQ Questions related to "Power" in Electrical Engineering. These Power MCQ Questions Will help you to improve your Electrical Engineering knowledge and will prepare you for various Examinations like Competitive Exams, Placements, Interviews and other Entrance Exmaniations.
The SI unit of power is the?
Explanation: The SI unit of power is the watt, one joule per second.
Electric power is the?
A. rate per unit time
B. voltage per unit time
C. electric charge per unit time
D. current per unit time
Explanation: Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit
Formula for Power is
A. P = VI
B. P = V/I
C. P = V+I
D. P = VQ
Explanation: Formula for Power is P = VI.
Which of the following statements are true?
A. Power is proportional to voltage only
B. Power is proportional to current only
C. Power is neither proportional to voltage nor to the current
D. Power is proportional to both the voltage and current
Explanation: Power is proportional to both voltage and current.
A 250V bulb passes a current of 0.3A. Calculate the power in the lamp.
Explanation: Here, V = 250v and I = 0.3A. P=VI. Which implies that, P=250*0.3=75W.
Kilowatt-hour(kWh) is a unit of?
Explanation: Power is the energy per unit time. That is, P=E/t. If the unit of power in kW and the unit of time is an hour, then the unit of energy=unit of power*unit of time=kWh.
A current of 5A flows in a resistor of 2 ohms. Calculate the energy dissipated in 300 seconds in the resistor.
Explanation: P=I^2R =5^2*2=50W. E= Pt=50*300=15000J=15kJ.
Electric power is transformed to other forms of energy when electric charges move through an electric potential (voltage) difference, which occurs in electrical components in electric circuits.
C. Can be true or false
D. Can not say
Explanation: Electric power is transformed to other forms of energy when electric charges move through an electric potential (voltage) difference, which occurs in electrical components in electric circuits.
From the standpoint of electric power, components in an electric circuit can be divided into?
A. three categories
B. four categories
C. five categories
D. two categories
Explanation: From the standpoint of electric power, components in an electric circuit can be divided into two categories: Passive devices and Active devices.
Calculate the work done in a resistor of 20 ohm carrying 5A of current in 3 hours.
Explanation: To find power: P=I^2R=5^2*20=500W=0.5kW. To find Work done: W=Pt=0.5*3=1.5kWh.