Question

One of the many by products of uranium is radioactive plutonium, which has a half life of approximatley 25000 ytears. if some of this putonium is encased in concrete, what fraction of it will remain after 100 years?

Answer 1

0.9972 fraction of plutonium will remain after 100 years.

Step-by-step explanation:

Half life of plutonium =
`t_(1/2)=25000 years`

Let the initial mass of plutonium be =
`A_o`

Mass of plutonium after time of 100 years = A

Decay constant for this process =
`\lambda =(0.693)/(t_(1/2))`

`A=A_o* e^(-\lambda t)`

`A=A_o* e^{-(0.693)/(25000 years)* 100 year}`

`A=A_o* 0.9972`

`(A)/(A_o)=0.9972`

0.9972 × 100 = 99.72 %

0.9972 fraction of plutonium will remain after 100 years.