Plutonium decays with a half-life of `24000` years. If the plutonium is stored for `72000` years, then the fraction of plutonium that remains is.

Explanation

`T_(1//2)=24,000 "years"`
Duration of time `(t)-= 72,000 "years"`
Number of half lifes `(n)=(t)/(T_(1//2))=(72000)/(24000)=3`
`:. 1g overset(1)rarr(1)/(2)g overset(2)rarr(1)/(4)goverset(3)rarr(1)/(g)g`
`:.` Fraction of plutonium remains `=(1)/(8) g`