Question

Kilowatt-hour is the unit of?
A- potential difference
B- electric power
C- electric energy
D- charge

Answer 1

Hint: Kilowatt-hour, as the name suggests, is referring to something which is measured every hour. We know there are different units to measure different quantities. Recall what is written on electrical appliances? Every appliance claims huge savings of energy, but in which units?

Complete step by step answer:Potential difference is defined as the difference between the potential at any predefined two points and it is always measured in Volts, so option (A) is incorrect.
The standard unit used to measure power is the watt (W). One watt is equal to one joule of work done in one second. Power is the rate of doing work. Power is measured in Watts. So, option (B) is incorrect.
The charge is measured in coulomb. So, option (D) is incorrect.
The electric energy that we consume in our households is measured in the units of a kilowatt-hour. So, the correct option is (C)

Additional information-: In a DC circuit, the power consumed is the product of the DC voltage times the DC, given in watts. However, for AC circuits this is not the case. For AC we have to take into account the power factor of the circuit.

Note:power rating nowadays is mentioned on every electrical appliance. If we say on the washing machine it is mentioned as 200 W, it means if we use it continuously for one hour that it will consume 0.2 units of electricity.