A radio active element "X" with a halflife of 2 hours decay giving a stable element"Y". After a time of "t" hours the ratio of atoms is 1:7 then, the value of
4 hours
6 hours
5 hours
14 hours
A radio active element "X" with a halflife of 2 hours decay giving a stable element"Y". After a time of "t" hours the ratio of atoms is 1:7 then, the value of