The probability of an atom disintegrating in any time interval is indenpendent of its past history and is the same for all atoms of the same kind.Let N is the total number of the atom, dN is the number of atom distingegrating in time interval dt
(dN/N)/dt = -p where p is the probability that decay will occurs.
so dN/N = -p dt
then we will haveN = No e-pt = No e-t/T where p=1/TNois the number of atoms at t=0, at t=T (called mean lifetime) N(T)=No e-1
We also define half-life T1/2 such that N(T1/2)=No/2
so T1/2 = log(2.) T = 0.693 T
A given radioactive decay can be a single step in a long sequence of transformation from one unstable nuclide to another.
There are three naturally occuring radioactive series beginning with 238U, 235U, and 232Th , all ending in different isotopes of lead.
For example: nuclide A will decay and become nuclide B, and nuclide B will decay and become nuclide C, ...
This applet will show how the population of each nuclide changed during radioactive decay series:
The applet shown radioactive decay from nuclide A(black) -> B(red) ->
C(green) -> D(yellow).
Each circle represent a nuclide.
For nuclide A decay into nuclide B : black circle will change into red circle.You can change decay time for each nuclide and see how the population for each nuclide change with time.
For nuclide A decay into nuclide B : red circle will change into green circle.
If you just want to see decay from A to B, and B is stable nuclide ->
click the checkbox at the top-right.
Your suggestions are highly appreciated! Please click firstname.lastname@example.org
Author¡GFu-Kwun Hwang, Dept. of physics, National Taiwan Normal UniversityLast modified : More physics related java applets