Radiation Safety Practice Exam

Which statement is true about gamma rays?

1. They can be easily blocked by skin.

2. They move at the speed of light.

3. They have mass similar to that of a proton.

4. They create ionization only in gases.

The correct answer is: They move at the speed of light.

Gamma rays are a form of electromagnetic radiation, and one of their defining characteristics is that they travel at the speed of light in a vacuum. This is true for all electromagnetic radiation, which includes not only gamma rays but also radio waves, microwaves, infrared radiation, visible light, and ultraviolet light. The ability to move at the speed of light is critical in understanding how gamma rays interact with matter and propagate through space. The other statements do not accurately reflect the properties of gamma rays. They are not easily blocked by skin, as their high penetration power requires denser materials like lead or several centimeters of concrete for effective shielding. Gamma rays do not possess mass similar to that of protons; in fact, they are massless particles. Finally, gamma rays can create ionization in various media, not just gases, which includes liquids and solids, thus broadening their impact and the importance of understanding their properties in radiation safety.