| Half-life: | The time during which half the number of atoms in the element disintegrate. |
| Heisenberg uncertainty principle: | It is impossible to have a particle that has an arbitrarily well-defined position and momentum at the same time. |
| Hertz: | The unit of frequency, also known as cycles per second. |
| Hooke's law: | Within elastic limit, stress is directly proportional to strain. |
| Horsepower: | unit of power, 1H.P. = 746 Watts. |
| Huygens'principle: | Each point on a light wavefront can be regarded as a source of secondary waves, the envelope of these secondary waves determining the position of the wavefront at a later time. |
|
|
|
