A piece of radioactive material contains 1020 atoms. If the half life of the material is 20 seconds, the number of disintegration in the first second is

A piece of radioactive material contains 1020 atoms.

If the half life of the material is 20 seconds, the number of disintegration in the first second is

Answer Details

The number of disintegration,∆N in time interval At, is given by
- ∆N = N∆t
Where N is the number of atoms present at the time t
But ^ = (0.693)/T
∴ ∆N = (0.693)/1(1)/2 N∆t = (0.693 x 10)20 x 10/20 = 3.47 x 1018