What does Half Life mean in Nuclear Terms?

Answer 1

Half life is the time it takes for 50% of a given substance to undergo radioactive decay. Note that all of the material will not undergo decay in twice the half life. After 2 HL's 2% will be left, then 12.5%, then 6.25, then 3.125....
It will take MANY half lives until the last atom undergoes decay.

Answer 2

The short answer is that if a substance has a half life of one year and you start now with one gram of it, after one year there will only be one half gram of the original material left. After another year has passed another half will be gone leaving only one quarter of a gram left. Half lives refer to nuclear materials that decay radioactively like radium and uranium. Some half lives are millions of years and other are fractions of a second. The radioactive decay may cause an atom's nucleus to give up an electron, a neutron or a gamma ray or even an alpha particle (which is the nucleus of a helium atom). Although half of the original material may be gone, the new element or isotope left in its place may be quite similar. For example uranium can decay in a number of steps to inert lead. Hope that helps a little.

Answer 3

1) SmartySlacks where did you learn English, it is in fact Nuclear, so don't correct people unless you're correct
2) A half life is the time it takes for a radioactive isotope to expend half of it's radioactive particles, over each half life, the remaining radioactive particles are halved. So the chain would be 50%, 25%, 12.5% And so on.

Answer 4

Half the time it takes a nuclear agent to decompose.
Depending on the material this can be a few dozen to over a 1000 years.

Answer 5

nuclear stuff decays exponentially, so the half life is the time it takes for half the sample to decay. ie 50 of a 100 whatevers will decay in the same time as 25 of the reaining 50.

Answer 6

The rate of decay for a radioactive isotope varies considerably. The half-life of a radioisotope is constant and independent of the sample size. The time that it takes for half of any sample to decay is called the half-life.

Answer 7

Half life is the time it takes for a substances radioactivity to drop to half.

ie: You read a rod of Uranium at 180 Bq.
It takes an hour to drop to 90 Bq.
The half life is 1 hour.

Simple. Please note that different substances have different half lives

Answer 8

The half life is the length of time it takes for a radioactive mass of a certain element to decay to half its original mass.

Answer 9

it means that after a chemical no longer has it's full effect, how long it will remain in existence in a stable form. for example, if you smoke marijuana, you will be high for lets say an hour, but the chemical THC still stays in your system for 30 days. The 30 days is the half-life. hope this helps.

Answer 10

If the "Half Life" of element XX is say1,000 years that means in 1.000 years it will be half as poisonous as it is today, thus in 2,000 years it will be a Quarter, 4,000 years an Eighth, and they try to kid us some of this muck is safe