Which beam characteristic causes energy to spread over a greater area, reducing intensity?

• A. Divergence
• B. Flashlight
• C. Atmosphere
• D. Reflectivity

Answer: (B)

Divergence is the beam’s spreading angle as it propagates. When a beam diverges, its cross-sectional area increases with distance, so the same total energy is distributed over a larger area, which lowers the energy per unit area or intensity. A beam with little divergence stays narrow longer and maintains higher intensity over distance. The other terms don’t describe how the beam itself expands: a flashlight is just the source, the atmosphere can scatter or absorb energy but isn’t the beam’s inherent spreading characteristic, and reflectivity concerns how surfaces reflect energy rather than how the beam expands.