Take a light ray passing from one medium to another of different optical density at right angles. The speed of the light will change but it will not change direction. The speed of the light has changed so something has happened to the light. What has happened? Does this constitute refraction? If not then what do you call this? This light has been ...


closed as unclear what you're asking by ZeroTheHero, Kyle Kanos, Yashas, honeste_vivere, JMac Jul 7 '17 at 16:58

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    $\begingroup$ In my opinion you might have misjudged your audience in your last sentence, :). What are your ideas about it, that's what people really want to know. $\endgroup$ – user154420 Jul 6 '17 at 15:05
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    $\begingroup$ According to Wikipedia refraction is the change in direction of wave propagation due to a change in its transmission medium. Assuming you accept this definition light normally incident on a surface is not refracted. I'm not sure I know of a single word for the change in velocity that occurs at a refractive index change. $\endgroup$ – John Rennie Jul 6 '17 at 17:01
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    $\begingroup$ So it slows down. Its frequency is invariant. What happens to its wavelength? $\endgroup$ – Cosmas Zachos Jul 6 '17 at 23:02
  • $\begingroup$ See for instance. $\endgroup$ – Cosmas Zachos Jul 6 '17 at 23:09