What fraction will be left after 1000 years? 2000 years? 4000 years?
2006-11-19 14:54:31 · 5 answers · asked by RITA 1 in Science & Mathematics ➔ Engineering
A Half Life is the amount of time it takes for the material to decay by half
For eg 1kg of uranium with 1000 Year Half Life
After 1000 Years .5kg would remain
After 2000 Years .25kg would remain
After 4000 Years .0625kg would remain
it's mass half's every 1000 years or whatever its half life is.
thats why with medicine they use materials with half life's of 12hrs so after 2 - 3 days the amount in your body will be miniscule i.e x rays...
2006-11-19 15:07:23 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Half life is the amount of time it takes for a radioactive substance to lose half of its mass.
If the half life is 1000 years, then after 1000 years (one half life) it will have lost half it's mass (1/2 * 1 = 1/2)
After 2000 years, it will have undergone two half lifes, and will be at 1/4 of it's mass (1/2 * 1/2 = 1/4)
After 4000 years, it will be at 1/16 of its beginning mass, because it will have been through 4 half lifes (1/2 * 1/2 * 1/2 * 1/2)
2006-11-19 23:06:36 · answer #2 · answered by Lottery 1 · 1⤊ 0⤋
A(t) = A(1/2)^(t/k)
A= mass of the substance
t= duration period: 1000 years, 2000 years, 4000 years.
k= constant: substance has a half-life of 1000 years.
w/o mass think it is:
A(t) = (1/2)^(t/k)
2006-11-19 23:13:10 · answer #3 · answered by ? 3 · 0⤊ 0⤋
Half life is the amount of time for 1/2 of a given amount of radioactive isotope to decay. It is not what the other answers suggest. one half of the mass is not gone,
only one have of the total number of atoms has decayed to another atom referred to as it's first daughter product. For example, in a nuclear reactor, the fission of Uranium 235 will yield xenon 135 which will decay eventually to strontium. In one half life, half the number of atoms of Xenon will have decayed. However, the decay product will still have substantial mass remaining. The total mass will only go down by a small amount, depending upon how it decays. But half the atoms will be the first decay product. The mass will still be close to the original mass.
2006-11-20 00:17:59 · answer #4 · answered by richard Alvarado 4 · 0⤊ 0⤋
This is an exponential question using the formula for radioactive decay. Just change the principle and time variables to solve it.
2006-11-19 22:59:47 · answer #5 · answered by Anonymous · 0⤊ 1⤋