Which statement accurately describes gamma photons?

• A. They have mass but no charge.
• B. They are produced only in beta decay.
• C. They are not penetrating.
• D. They can travel long distances through air and body tissue.

Answer: (D)

Gamma photons are massless, chargeless packets of electromagnetic energy. Because they carry no charge and have no rest mass, they interact with matter less readily than charged particles, so they can propagate significant distances through air and through body tissue before being absorbed. This strong penetrating power means shielding must be thick and dense (like lead or concrete) to reduce their intensity. That’s why the statement about gamma rays traveling long distances through air and tissue is correct. The other ideas don’t fit: gamma photons don’t have mass, they aren’t produced exclusively in beta decay (they’re emitted in many nuclear processes), and they are indeed penetrating rather than non-penetrating.