Ques. What is the electrical unit of power?
Ans. The watt.
Ques. What is a watt?
Ans. It is the power due to a current of one ampere flowing at a pressure of one volt. One watt = one ampere × one volt. It is equal to one joule per second.
Ques. What is a kilowatt?
Ans. 1,000 watts.
The Watt-Hour.—The elements which may be measured are, however, not only the volume of current, the unit of which is the ampere, and time, the unit of which is the hour, but also the pressure, the unit of which is the volt.
It is evident that a perfect system of electrical measurement should take account of the total amount of energy consumed, and should depend not only upon the volume of current, but also upon the pressure at which the current is applied.
The basis of such a system if provided in a unit which is the product of the two units of current and pressure, and which is termed a volt-ampere or watt.
The watt-hour represents the amount of work done by an electric current of one ampere strength flowing for one hour under a pressure of one volt.