In a radioactive material the activity at time t1 is R1 and later time at t2, it is R2. If the decay constant of the material is λ, then:
The radioactivity of a sample is R1 at a time T1 and R2 at a time T2. If the half-life of the specimen is T, the number of atoms that have disintegrated in the time (T2-T1) is proportional to:
The half life of a ratio active source is T. If radio activities of the samples are R1−R2 at time
T1 and T2 Respectively, then the number of atoms disintegrated in time (T2−T1) is proportional to