| slovo | definícia |
half-life
(encz) | half-life,poločas n: Zdeněk Brož |
half-life
(encz) | half-life,poločas rozpadu Zdeněk Brož |
Half-life
(gcide) | Half-life \Half"-life`\ (h[aum]f"l[imac]f`), n. (Physics)
the time it takes for one-half of a substance decaying in a
first-order reaction to be destroyed. For radioactive
substances, it is the time required for one-half of the
initial amount of the radioactive isotope to decay. The
half-lifeis a measure of the rate of the reaction being
observed. For processes that are true first-order processes,
such as radioactive decay, the half-life is independent of
the quantity of material present, and it is thus a constant.
The time it takes for one-half the remaining quantity of a
radioactive isotope to decay will be the same regardless of
how far the decay process has advanced. Some chemical
reactions are also first order, and may be characterized as
having a half-life. However, for chemical reactions the
half-life will depend upon temperature and in some cases
other environmental conditions, whereas for radioactive
isotopes the rate of decay is largely independent of the
environment.
[PJC] |
half-life
(wn) | half-life
n 1: the time required for something to fall to half its initial
value (in particular, the time for half the atoms in a
radioactive substance to disintegrate) [syn: half life,
half-life] |
| | podobné slovo | definícia |
Half-life
(gcide) | Half-life \Half"-life`\ (h[aum]f"l[imac]f`), n. (Physics)
the time it takes for one-half of a substance decaying in a
first-order reaction to be destroyed. For radioactive
substances, it is the time required for one-half of the
initial amount of the radioactive isotope to decay. The
half-lifeis a measure of the rate of the reaction being
observed. For processes that are true first-order processes,
such as radioactive decay, the half-life is independent of
the quantity of material present, and it is thus a constant.
The time it takes for one-half the remaining quantity of a
radioactive isotope to decay will be the same regardless of
how far the decay process has advanced. Some chemical
reactions are also first order, and may be characterized as
having a half-life. However, for chemical reactions the
half-life will depend upon temperature and in some cases
other environmental conditions, whereas for radioactive
isotopes the rate of decay is largely independent of the
environment.
[PJC] |
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