Question

The radioactive ⁹⁰Sr that is formed due to nuclear explosion has half life period of 28.1 years. In the body of a child born at this time ⁹⁰Sr is found to be 1μg (10⁻⁶ gram), then what will be ⁹⁰Sr left in the body of the child when (a) the age of the child will be 20 years and (b) when the age of child will be 70 years. (⁹⁰Sr is not lost in any other way).Calculate the given example.

Answer 1

Explanation:

t half = 0.693/k

k = 0.693 /28.1= 0.0246

t = (2.303/0.0246)× log( 1mewg/A)= 20

A= 0.611 mew g

t=70 = (2.303/0.0246)× log( 1mewg/A)

A = 0.1787 mew g