The Intensity of Gamma Rays Passing Through a Material as a Function

question 86

Multiple Choice

The intensity of gamma rays passing through a material as a function of thickness, x is given by where n is the number of atoms per cm³ and $\sigma$ is the absorption cross section. It is observed that the intensity of gamma rays of a particular energy is reduced by half when they passed through 1 cm of lead. What is the thickness of lead needed to reduce the intensity to a quarter?

• A) 1.0 cm
• B) 1.5 cm
• C) 2.0 cm
• D) 3.0 cm
• E) 4.0 cm