Question

The half-life of ${}^{32}\text{P}$ is 14.3 day. The specific activity of a phosphorus containing specimen having 1.0 part per million ${}^{32}\text{P}(At.Wt.ofP=31)$ is :

• A. [0.295 Ci/g]
• B. [0.595 Ci/g]
• C. [0.795 Ci/g]
• D. None of these

Answer 1

The correct option is A [0.295 Ci/g]

The half life period $t_{1/2}\frac{0.693}{\lambda }=\frac{0.693}{14.3\times 24\times 3600}$
Also $\frac{-dN}{dt}=\lambda N=\frac{0.693}{14.3\times 24\times 3600}\times \frac{1}{32\times 1000000}\times 6.023\times {10}^{23}\times \frac{1Ci}{3.7\times {10}^{10}dps}=0.295Ci/g$