Question

Give an SI unit and commercial unit of energy.

Answer 1

Hint:Energy is the ability and necessity to be possessed by the body to do work. Energy can be found in many things and can take different forms. We have seen in food packets and ready to cook food it is always mentioned how much energy it will give, since, it is defined as the ability to do work it has to be measured in units.

Complete step by step answer:
Energy can take different forms such as kinetic, potential, electrical, chemical, nuclear, thermal, etc. The SI unit of measuring energy is Joules, denoted by the symbol J. 1 joule is defined as the amount of work done when the force of 1 N acts on a body and the displacement is 1 m.
Commercial units of energy are needed when large quantities of energy are to be expressed and this is used in industries and factories. The commercial unit of energy is Kilowatt-hour denoted by kWh. One kilowatt-hour is defined as the amount of energy that is consumed by a machine in one hour working at a constant rate of one kilowatt.
Hence, an S.I unit of energy is joule and the commercial unit is Kilowatt-hour.

Note:Another common unit of energy is watt-hour and others are horsepower. Work and energy have the same units and energy is a scalar quantity. There is a relationship between the SI unit of energy and the commercial unit of energy.
1 kWh = 1kW $\times$ 1h = 1000W $\times$ 1h = 1000(J/s) $\times$ 3600 s = 3.6 $\times {10}^6$J.