critical angle
Definition
- Noun:
- The smallest angle of incidence for which light is totally reflected: In optics, the critical angle is the specific angle of incidence at which a light ray traveling from a denser medium to a less dense medium is refracted at an angle of 90 degrees. For any angle of incidence greater than this, total internal reflection occurs.
Usage Examples
- Noun:
- The critical angle for the water-air interface is approximately 48.6 degrees.
- To achieve total internal reflection in the fiber optic cable, the light must strike the core-cladding boundary at an angle greater than the critical angle.
Advanced Usage
- "Exceed the critical angle": To have an angle of incidence larger than the critical angle, resulting in total internal reflection.
- When the light exceeds the critical angle, it is completely reflected back into the medium.
Variants and Related Words
- Total internal reflection (n): The complete reflection of a light ray back into its original medium when it strikes the boundary at an angle greater than the critical angle.
- Total internal reflection is the principle behind the operation of optical fibers.
Synonyms
- Angle of total reflection: A less common synonym for the critical angle.
- Limiting angle: Another term sometimes used to describe the critical angle.
Related Phrases
- Brewster's angle: A different optical concept; the angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent surface without reflection.
- Brewster's angle is important for reducing glare in optical devices.
Noun
-
the smallest angle of incidence for which light is totally reflected
