During nuclear explosion, one of the products is `90_{Sr}` with half-life of 28.1 years. If `1 mu g` of `90_{Sr}` was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years and 60 years if it is not lost metabolically.

One of the harzards of nuclear explosion is the generation of ""^(90)Sr and its subsequent incorporation in bones. This nuclide has a half-life of 28.1 years. Suppose one microgram was absorbed by new born child, how much ""^(90)Sr will remain in his bones after 20 years.

The radioactive isotope tritum ( ""_(3)^(1)H) has a half life 0f 12.3 years. IF the initial amount of tritium is 32 mg, how many milligrams of it would remain after 49. 2 years ?

A radioactive sample has a half- life of 1500 years. A sealed tube contains 1 g of the sample. How much quantity of sample will be left after 3000 years?