Value
A gram of TNT releases 4100–4602 joules upon explosion. To define the tonne of TNT, this was arbitrarily standardized by letting 1 gram TNT = 4184 J (exactly). This conveniently defined the energy liberated by one gram of TNT as exactly one kilocalorie.
This definition is a conventional one. The explosive's energy is normally calculated using the thermodynamic work energy of detonation, which for TNT has been accurately measured at 4686 J/g from large numbers of air blast experiments and theoretically calculated to be 4853 J/g.
The measured pure heat output of a gram of TNT is only 2724 J, but this is not the important value for explosive blast effect calculations.
Alternative TNT equivalency can be calculated depending upon when in the detonation the value is measured and which property is being compared.
A kiloton of TNT can be visualized as a cube of TNT of 8.46 metres (27.8 ft) on a side.
| Grams TNT | Symbol | Tons TNT | Symbol | Energy |
|---|---|---|---|---|
| gram of TNT | g | microton of TNT | μt | 4.184×103 J |
| kilogram of TNT | kg | milliton of TNT | mt | 4.184×106 J |
| megagram of TNT | Mg | ton of TNT | t | 4.184×109 J |
| gigagram of TNT | Gg | kiloton of TNT | kt | 4.184×1012 J |
| teragram of TNT | Tg | megaton of TNT | Mt | 4.184×1015 J |
| petagram of TNT | Pg | gigaton of TNT | Gt | 4.184×1018 J |
Read more about this topic: TNT Equivalent
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