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| abstraction > mathematical concept > number > quantity > time > half-life |
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| half-life comparison table | ||||
| Subject | see also | is a kind of | has symbol | has definition |
|---|---|---|---|---|
| time | quantity | A dimension distinguishing past, present, and future. In relativity, time is portrayed as a geometrical dimension, analogous to the dimensions of space. | ||
| half-life | mean life | time | τ1/2 | Time it takes for the number of particles to halve. For a radioactive substance, the length of time required for half the atoms to disintegrate. |