The deacy time `t` for radioactive element proceeds to `4` half-lives. The total decay time `(t)` in terms of average life `(T)` is given by:

The decay constant of a radioactive sample is lamda. Its half -life is T_(1//2) and mean life is T.

A radioactive species undergoes decay for time t where t = 4t_(1//2) . The average life (T) of species can therefore be given by:

The half life of radioactive substance is T. Then the fraction of the substance that has decayed in time t is-

The half life of radioactive substance is T. Then the fraction of the substance that has decayed in time t is-

20% radioactive sample decay in time t. How much sample decay in time 2t ?

Time taken of decay for a nuclear reaction is given by t=4t_(1//2) . The relation between the mean life (T) and time of decay (t) is given by :

The graph between number of decayed atoms N' of a radioactive element and time t is.