Question

Choose the correct statement concerning units of power or energy. a. A kilojoule (kJ) is a unit of power. b. A gigawatt (GW) is a unit of energy. c. A watt (W) is a unit of energy. d. A kilowatt x hour per year (kWh/yr) is a unit of energy. e. A kilowatt (kW) is a unit of power.

Answer 1

Answer:

A kilowatt (kW) is a unit of power.

Explanation:

The power of an object is given by :

$P=\dfrac{E}{t}$

Here,

E is the energy required

t is time

The SI unit of power is Watts and the SI unit of energy is Joule. the commercial unit of energy is kilowatt per hour.    

Option (1) :  A kilojoule (kJ) is a unit of power is incorrect.

Option (2) : A gigawatt (GW) is a unit of energy is incorrect.

Option (3) : A watt (W) is a unit of energy is incorrect.

Option (4) : A kilowatt x hour per year (kWh/yr) is a unit of energy is incorrect.

Option (4) : A kilowatt (kW) is a unit of power is correct.

Hence, the correct option is (d).