The layman often uses the words energy
and power interchangeably. However, in science, these two words have very
distinct meanings. To understand what is meant by the terms energy and power,
an analogy with the flow of water may be used. Consider a tap from which there is a flow of water of 5 liters per minute. The volume of water delivered in a particular amount of time is equal to the flow multiplied by time. This relationship is given in equation form below. Note that we can also say that the flow is the rate at which volume is delivered. Thus, if the tap is left open for 2 minutes, the total volume of water which will be delivered is 5 * 2 = 10 litres. The connection between energy/power and volume/flow is simple: we can think of energy to be like volume and power to be like flow. With this analogy in mind, we get the following two equations. Therefore, just as flow is the rate at which volume is delivered; power is the rate at which we use energy. 
Watt, kilowatt and kilowatthour


WATT KILOWATT 



KILOWATT HOUR 