# Electric Energy

The capacity for doing work possessed by electricity under proper conditions. Electric energy may be either kinetic or potential. As ordinary mechanical energy is a product of force and space, so electric energy is a product of potential difference and quantity. Thus a given number of coulombs of electricity in falling a given number of volts develop electric energy. The dimensions are found therefore by multiplying electric current intensity quantity   ((M^.5) * (L^.5)), by electric potential   ((M^.5)*(L^1.5) / (T^2)), giving (M * (L^2)/(T^2)), the dimensions of energy in general as it should be.

The absolute unit of electric energy in electro-magnetic measure is (1E-7) volt coulombs.

The practical unit is the volt-coulomb. As the volt is equal to 1E8 absolute units of potential and the coulomb to 0.1 absolute units of quantity, the volt-coulomb is equal to 1E7 absolute units of energy.

The volt-coulomb is very seldom used, and the unit of Electric Activity or Power (see Electric Power), the volt-ampere, is universally used. This unit is sometimes called the Watt, q. v., and it indicates the rate of expenditure or of production of electric energy.

The storing up in a static accumulator or condenser of a given charge of electricity, available for use with a given change of potential represents potential electric energy.

The passing of a given quantity through a conductor with a given fall of potential represents kinetic electric energy.

In a secondary battery there is no storage of energy, but the charging current simply accumulates potential chemical energy in the battery, which chemical energy is converted into electric energy in the discharge or delivery of the battery.

It is customary to discuss Ohm's law in this connection; it is properly treated under Electric Power, to which the reader is referred. (See Electric Power)

[Transcriber's note: A volt-ampere or watt is a unit of power. A volt-coulomb-second or watt-second is a unit of energy. Powermultiplied by time yields energy.]