A radio nuclide consists of two isotopes. One of the isotopes decays by α -emission and other by β -emission with half-lives T1=405 s and T2=1620 s , respectively. At t=0 , probabilities of getting α and β -particles from the radio nuclide are equal. Calculate their respective probabilities at t=1620 s . If at t=0 , total number of nuclei in the radio nuclide are N0 . Calculate the time t when total number of nuclei remained undecayed becomes equal to N0/2 .
log102=0.3010,log105.94=0.7742 and x4+4x−2.5=0,x=0.594