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What is nicol prism?

Nicol prism Nicol prism was invented by William Nicol in 1828. It is an optical device used for producing and analyzing plane polarized light. The nicol prism is made in such a way that it eliminates one of the two rays by total internal reflection. It is generally found that it eliminates the ordinary ray … Read more

What do you understand by double refraction?

Double refraction Erasmus Bartholinus discovered in 1669, that, when a ray of light is refracted by a crystal of calcite it gives two refracted rays. This phenomenon is called double refraction. Calcite is crystallized calcium carbonate (CaCO3). It crystallizes in many forms and can be reduced by cleavage or breakage into a rhombohedra.

Define phase velocity and group velocity?

Phase velocity Phase velocity is the velocity with which a plane progressive wave front travels forward. Phase velocity is symbolized by . It has a constant phase =  Group velocity The group velocity () is the speed with which the point of reinforcement of the resultant wave travels. The group velocity is different from the individual … Read more