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physical phenomena > process > physical process > optical process > radiation modification > radiation direction modification > refraction

refraction
subject			fact

refraction	obeys Snell's law
	has definition Deflection (or "bending") of light - or any ray as it passes from one medium into another of greater or lesser density, representing a change in overall speed of the ray. Refracting telescopes rely on the refraction of light through lenses. The refractive index of a medium (e.g., glass) is a measure of the medium's "bending" power.
	is a kind of radiation direction modification
radiation direction modification	changes property direction
optical process	has domain optics

Kinds of refraction :

• astronomical refraction (2 facts) - The change in direction of travel (bending) of a light ray as it passes obliquely through the atmosphere. As a result of refraction, the observed altitude of a celestial object is greater than its geometric altitude. The amount of refraction depends on the altitude of the object and on atmospheric conditions.