Watt-hour (Energy)
From The Encyclopedia of Earth
Watt-hour
January 6, 2007, 6:36 pm
| Topics: |
| SI multiples of watt-hour | ||||||
|---|---|---|---|---|---|---|
| Multiple | Name | Symbol | Multiple | Name | Symbol | |
| 100 | watt-hour | W·h | ||||
| 101 | decawatt-hour | daW·h | 10–1 | deciwatt-hour | dW·h | |
| 102 | hectowatt-hour | hW·h | 10–2 | centiwatt-hour | cW·h | |
| 103 | kilowatt-hour | kW·h | 10–3 | milliwatt-hour | mW·h | |
| 106 | megawatt-hour | MW·h | 10–6 | microwatt-hour | µW·h | |
| 109 | gigawatt-hour | GW·h | 10–9 | nanowatt-hour | nW·h | |
| 1012 | terawatt-hour | TW·h | 10–12 | picowatt-hour | pW·h | |
| 1015 | petawatt-hour | PW·h | 10–15 | femtowatt-hour | fW·h | |
| 1018 | exawatt-hour | EW·h | 10–18 | attowatt-hour | aW·h | |
| 1021 | zettawatt-hour | ZW·h | 10–21 | zeptowatt-hour | zW·h | |
| 1024 | yottawatt-hour | YW·h | 10–24 | yoctowatt-hour | yW·h | |
Definition
The watt-hour (symbol W·h) is a unit of energy commonly used to measure electricity. One watt-hour is the amount of electrical energy equivalent to a one-watt load drawing power for one hour. For example, a 100-watt light bulb uses 100watt-hours of energy every hour. The is commonly used in the form of the kilowatt-hour, which is 1,000 watt-hours. The watt-hour It is not an SI unit, despite being based on the watt. The SI unit of energy is the joule (J), equal to one watt-second.
In the inch-pounds unit system, a watt-hour is equivalent to 3.412 Btu.
Further reading
- How Many? A Dictionary of Units of Measurement, Russ Rowlett, Center for Mathematics and Science Education, University of North Carolina at Chapel Hill
- SI base units and SI derived units, the Physics Laboratory, National Institute of Standards and Technology
- Energy conversion tool at unitconversion.org
