RADIOACTIVITY
DOE-HDBK-1019/1-93
Atomic and Nuclear Physics
NP-01
Page 34
Rev. 0
Example:
A sample of material contains 20 micrograms of californium-252.
Californium-252 has a half-life of 2.638 years.
Calculate:
(a)
The number of californium-252 atoms initially present
(b)
The activity of the californium-252 in curies
(c)
The number of californium-252 atoms that will remain in 12 years
(d)
The time it will take for the activity to reach 0.001 curies
Solution:
(a)
The number of atoms of californium-252 can be determined as below.
(b)
First, use Equation (1-6) to calculate the decay constant.
Use this value for the decay constant in Equation (1-3) to determine the activity.
