index of refraction
Học thuậtThân thiện
Definition
Noun The ratio of the speed of light in a vacuum to its speed in a specific medium. This dimensionless number quantifies how much a ray of light bends, or refracts, when it enters that material from a vacuum or air.
Usage
The term "index of refraction" is used in physics and optics to describe a fundamental optical property of transparent materials. * The index of refraction of water is approximately 1.33. * Diamonds have a very high index of refraction, which contributes to their brilliance. * To design the lens, the engineer needed to know the precise index of refraction of the glass.
Advanced Usage
- "Index of refraction" is often symbolized by the lowercase letter in equations (e.g., Snell's Law: n₁sinθ₁ = n₂sinθ₂).
- The index of refraction for a material typically varies with the wavelength of the incident light; this dependence is called dispersion.
Variants and Related Words
- Refractive Index: This is a direct synonym and is used interchangeably with "index of refraction."
- Refraction (n): The bending of a wave, such as light, when it passes from one medium into another.
- Refract (v): To cause light to change direction as a result of entering a medium with a different density.
Synonyms
- Refractive index
Related Scientific Concepts
- Snell's Law: The formula that relates the angles of incidence and refraction to the indices of refraction of the two media.
- Dispersion: The phenomenon where the index of refraction of a material depends on the light's wavelength, causing separation of colors (as in a prism).
- Critical Angle: The angle of incidence beyond which total internal reflection occurs, which is determined by the indices of refraction of the two media.
Noun
- the ratio of the velocity of light in a vacuum to that in a medium