== Current and Power and Energy
== The unit used to measure the flow of electricity, or current, is the ampere (A). The unit to measure power is the watt (W). Energy is measured in Joules (J). Amperes are really a measure of a rate of electron flow (electrons per second), or equivalently, how much charge is passed per second (Coulombs per second). 1 A = 1 Coulomb per second, and 1 electron has a charge of 1.602 * 10-19 Coulombs.
Power is measure in watts. A watt is an amount of energy per second, or Joules per second (1 W = 1 J/s). The number of watts is for an electrical circuit given by the number of amperes times the voltage drop: 1 W = 1 V * 1 A.
A power company supplying electricity wants to know how much energy (that's Joules) you have used. How much power (that's Watts) you use changes during the day... you turn on the toaster or microwave, your power usage goes up, and at night, you power usage goes down. But the amount of energy you use is the sum of that averaged over time (more precisely, it is the integral of your power consumption, or the area under your power consumption curve).
Energy is measured in Joules (in SI units), but power companies use funny units of kilowatt hours (kW hr). Since a watt is just a joule per second (J/s), a kilowatt hour is a measure of energy. Here is how you convert:
1 kW hr = 1000 W hr = 1000 J/s hr = 1000 J/s * 3600 s = 3.6 * 106 J or 3.6 million Joules
The power company doesn't use Joules on your electricity bill because we use a lot of them... instead they use kilowatt hours... but that's just a bunch of Joules.
Watts. Also for any other type of power (energy / time), that is, for transfer of energy that is not electrical in nature.
The unit used for ANY type of energy is the joule.
In the United Kingdom, electricity companies charge their customers by the unit. The term 'unit' is short for the obsolete expression 'Board of Trade Unit' and is a measurement of electrical energy, equivalent to a kilowatt hour. So, 1 unit = 1 kW.h
work and energy +++ The Joule (J) is the unit of energy, alone, not of work. The Watt (W) is the unit of power, i.e. work done in converting or transferring energy, and 1W = 1J/s.
Energy of heat = Joules (J)
Watts. Also for any other type of power (energy / time), that is, for transfer of energy that is not electrical in nature.
The Watt is the unit used to measure electric power :)
I am not quite sure what you mean; electric energy is measured in the same units as any other types of energy - typically the joule.
If you refer to the unit, the international unit for energy is the joule; the symbol is "J".
The coulomb is the unit used to measure electric charge.
The unit used to measure the energy of an electromagnetic wave is called a photon.
The unit used to measure electric charge in the International System of Units (SI) is the coulomb (C).
kilowatts
volt (V)
The international unit for energy (and work) is the joule.
The joule.
Calorie is the unit used to express chemical energy in food.