Diffuse reflection occurs when a laser beam is reflected off what?

• A. a non-reflective or uneven surface
• B. a smooth mirror
• C. a transparent sheet
• D. a polished metal surface

Answer: (A)

Diffuse reflection happens when light encounters a rough, uneven surface. That roughness means the surface is made up of countless tiny facets facing in different directions. Each facet reflects part of the incoming laser beam in its own direction, so the reflected light spreads out, scattering in many directions rather than traveling as a single beam. That’s why a laser beam won’t form a sharp image on such a surface and instead appears as a diffuse glow.

In contrast, a smooth mirror or a polished metal surface acts like a single plane, producing specular reflection where the angle of incidence equals the angle of reflection, giving a clear, focused reflection of the beam. A transparent sheet mainly transmits light with refraction and some surface reflection, but it doesn’t produce the wide, scattered reflection characteristic of a rough surface.