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Symbol | Definition |
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≡ | exactly equal |
≈ | approximately equal to |
= | equal to |
digits | indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …) |
The gigajoule (GJ) is equal to one billion (109) joules. 6 GJ is about the chemical energy of combusting 1 barrel (160 l) of crude oil. 2 GJ is about the Planck energy unit.
The therm (symbol thm) is a non-SI unit of heat energy equal to 100,000 British thermal units (BTU). It is approximately the energy equivalent of burning 100 cubic feet (2.83 cubic metres) – often referred to as 1 CCF – of natural gas.