Chapter 24, Problem 77A

Interpretation Introduction

Interpretation:

The position of worker B from the source needs to be determined.

Concept introduction:

Gamma rays are photons, which are high-energy(short wavelength) electromagnetic radiation. They are denoted by the symbol $\text{γ}$.

Answer to Problem 77A

The distance of the worker at position B is 3.5m.

Explanation of Solution

Given information,

$\begin{array}{l}{\text{I}}_1=\text{0}{\text{.98mrem/ms}}^{\text{2}}\\ {\text{I}}_{\text{2}}=\text{0}{\text{.50mrem/ms}}^{\text{2}}\\ {\text{d}}_{\text{1}}=\text{2}\text{.5m}\end{array}$

The relation between intensity and distance is

$\begin{array}{l}{\text{I}}_{\text{1}}{\text{d}}_{\text{1}}{}^{\text{2}}={\text{I}}_{\text{2}}{\text{d}}_{\text{2}}{}^{\text{2}}\\ {\text{d}}_{\text{2}}{}^{\text{2}}=\frac{{\text{I}}_{\text{1}}{\text{d}}_{\text{1}}{}^{\text{2}}}{{\text{I}}_{\text{2}}}\\ {\text{d}}_{\text{2}}{}^{\text{2}}=\frac{(0.98){(2.5)}^2}{0.5}\\ {\text{d}}_{\text{2}}{}^{\text{2}}=12.25\\ {\text{d}}_{\text{2}}=\sqrt{12.25}\\ {\text{d}}_{\text{2}}=\text{3}\text{.5m}\end{array}$

Conclusion

The best way to get less intensity of radiation is just move away from the source.