Half-life period of a radioactive element is 100 seconds. Calculate the disintegration constant and average life. How much time will it take to lose its activity by `90%`?

Explanation

`k=(0.693)/(t_(1//2))=(0.693)/(100s)=0.00693s^(-1)" "," ""Average life "(pi)=(1)/(k)=(1)/(0.00693s^(-1))=144.3s`
Loss of `90%` activity means `(N_(0))/(N)=(100)/(100-90)=10" "," "t=(2.303)/(k)log""(N_(0))/(N)=(2.303)/(0.00693s^(-1))log10=332.3s`