Question

The activity of the solution in terms of counting per minute per mL at a counting efficiency of $80\%$ is :

• A. $35.6\times {10}^{5}cpmm{L}^{-1}$
• B. $88.8\times {10}^{7}cpmm{L}^{-1}$
• C. $79.8\times {10}^{6}cpmm{L}^{-1}$
• D. none of these

Answer 1

The correct option is B $88.8\times {10}^{7}cpmm{L}^{-1}$

1 curie = $3.7\times {10}^{10}dps$
$=3.7{10}^{10}\times 60dpm$
$=3.7{10}^{10}\times 60\times \frac{80}{100}countingmi{n}^{-1}$
$1mCi=3.7\times {10}^{10}\times 60\frac{80}{100},\times {10}^{-3}cpm$
$cpmm{L}^{-1}=3.7\times {10}^{10}\times 60\frac{80}{100}\times \frac{{10}^{-3}}{2}$
$88.8\times {10}^{7}cpmm{L}^{-1}$