Ordinary ray definitions

ordinary ray

(from the article `double refraction`) ...is split into two rays, each traveling in a different direction. One ray (called the extraordinary ray) is bent, or refracted, at an angle as it ...
Found on http://www.britannica.com/eb/a-z/o/28

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ordinary ray

the beam that does not deviate upon being split by a birefringent crystal.
Found on http://www.chemistry-dictionary.com/definition/ordinary+ray.php

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ordinary ray

the part of a doubly refracted ray whose velocity within a crystal is the same in any direction.
Found on https://www.infoplease.com/dictionary/ordinary-ray

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