The probaility that a certaun radioactive atom would get disintefrated in a time equal to the mean life fo the radioactive sample is

Explanation

Since , the Probability P(t) that a particular radioactive atom gets disintegrated in a time t (from Eq.) given by
`P(t)=1-e^(-lambdat)`
`therefore` Here `t= lt t gt =1/lambda " " therefore P(t)=1-1//e`
`approx` 1-0.37=0.63