Which description best describes a plane mirror?

Which description best describes a plane mirror?

• A. A curved mirror
• B. A lens that refracts light
• C. A mirror with a flat surface
• D. A ray of light traveling toward a mirror

Answer: (C)

Plane mirrors have flat surfaces that reflect light without bending it. When light hits the flat surface, it reflects at the same angle it arrived, so the image appears behind the mirror at the same distance as the object is in front. This makes the image virtual, upright, and the same size as the object. The other descriptions refer to different optical devices or phenomena: a curved mirror changes light paths because its surface isn’t flat, a lens bends light by refraction rather than reflection, and a ray of light traveling toward a mirror is just a light path, not a description of the mirror itself.

Plane mirrors have flat surfaces that reflect light without bending it. When light hits the flat surface, it reflects at the same angle it arrived, so the image appears behind the mirror at the same distance as the object is in front. This makes the image virtual, upright, and the same size as the object. The other descriptions refer to different optical devices or phenomena: a curved mirror changes light paths because its surface isn’t flat, a lens bends light by refraction rather than reflection, and a ray of light traveling toward a mirror is just a light path, not a description of the mirror itself.