18. A given number of atoms No of a radioactive element with a half life T is uniformly distributed in the blood stream of a
(i) normal person A having total volume V of blood in the body
(ii) person B in need of blood transfusion having a volume V′ of blood in the body.
The number of radioactive atoms per unit volume in the blood streams of the two persons after a time nT are found to be N1 and N2.
Prove mathematically that the additional volume of blood that needs to be transfused in the body of person B equals ( N2− N1/N2 ) V