law of reflection

American  

noun

1. the principle that when a ray of light, radar pulse, or the like, is reflected from a smooth surface the angle of reflection is equal to the angle of incidence, and the incident ray, the reflected ray, and the normal to the surface at the point of incidence all lie in the same plane.

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Usage

What is the law of reflection? While it may sound like a form of meditation, the law of reflection is a principle about what light does when it hits a perfectly smooth surface, like a mirror. The law states that light will bounce off such a surface at the exact same angle it hit that surface at.

Example Sentences

Use the law of reflection to prove that the focal length of a mirror is half its radius of curvature.

From Textbooks • Aug. 12, 2015

The law of reflection is illustrated in Figure 25.3, which also shows how the angles are measured relative to the perpendicular to the surface at the point where the light ray strikes.

From Textbooks • Aug. 12, 2015

Any ray striking the center of a mirror is followed by applying the law of reflection; it makes the same angle with the axis when leaving as when approaching.

From Textbooks • Aug. 12, 2015

Figure 27.6 shows how a mirror reflects an incoming wave at an angle equal to the incident angle, verifying the law of reflection.

From Textbooks • Aug. 12, 2015

We have illustrations of this law of reflection in the case of water waves striking against a breakwater, or a sound wave striking against the wall of a room.

From Aether and Gravitation by Hooper, William George