Question

What is the commercial unit of electrical energy?

Answer 1

Hint: We will talk about how Kilowatt-hour is the most commonly used commercial unit of electricity and how it compares to the SI unit of energy that is Joules. We will also write about why we don’t use Joules, the reason being this unit is extremely small when it comes to real-life energy requirements.

Complete step-by-step answer
Commercial unit of electrical energy used in our houses and industry is kWh or Kilowatt-hour. It is defined as the total energy consumed if an appliance runs at 1-kilowatt power for one hour. In SI units it means energy is consumed at a rate of 1000 Joules per second for an hour. If we calculate it in Joules, it comes out to be
$1000\times 60\times 60=3600000$Joules.
That is 3.6 million Joules of energy. This unit is not a standard unit in any of the formal measurement systems but still is used most commonly. This same unit is used for both electrical energy consumed in the commercial sector as well as the residential sector. However, the rates for both the commercial sector and the domestic sector are different.
Additional Information: Although Joule is the SI unit of energy is not used in the real world. This is because one Joule of energy is an extremely small amount of energy. Just for perspective, one liter of Petrol has about 32 million Joules of energy. We can see how using the SI unit would be very tedious and make things more complicated by bringing in very large numbers.

Note: The student must note that although Watt or Kilowatt are units of power. Kilowatt-hour is a unit of energy as we multiply a unit of time here with a unit of power, so we get a unit of energy on their multiplication. Sometimes large consumers are also billed extra for using a large amount of power for a short amount of time. This is to account for the excess infrastructure needed to provide a high amount of energy.