Advanced Patient Assessment Practice Exam

The ability of x-rays to penetrate matter is inversely proportional to which of the following physical properties of matter?

1. Density

2. Weight

3. Diffusion

4. Viscosity

The correct answer is: Density

The ability of x-rays to penetrate matter is indeed inversely proportional to density. This means that as the density of a material increases, the penetration power of x-rays decreases. Denser materials contain more mass per unit volume, which leads to a greater likelihood of x-ray photons being absorbed or scattered as they interact with the particles in the material. Comparatively, the other physical properties listed—weight, diffusion, and viscosity—do not directly relate to the penetration capability of x-rays in the same way density does. Weight is a measure of the force of gravity on an object and does not account for the interaction of x-rays with the atomic structure of a material. Diffusion refers to the movement of particles from an area of higher concentration to one of lower concentration and is generally unrelated to the properties of x-ray penetration. Viscosity describes the resistance of a fluid to flow and is more about the behavior of liquids than the absorption characteristics of materials in relation to x-ray exposure. Therefore, density is the correct answer as it specifically relates to the absorption and attenuation of x-rays.