Experiment to find fringe width using biprism

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Experiment to find fringe width using biprism

An optic bench is used in the exp. It consists of a heavy metallic base with vertical stands for the slits, biprism, lens & eye-piece. The slits, eye-piece & biprism are adjusted so that well-defined bright & dark are obtained.
The cross wire of eye-piece is made to coincide with the central bright band & the reading of micrometer is noted as x1.
The eye-piece is moved until it crosses a definite no. of bright bands(say 20).The reading of micrometer is noted as x2. The diff between micrometer readings,i.e.,x2-x1,gives width of 20 bands. Then the width of one band (beta) can be calculated.

hope this helps. cheers

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Thank u anjana..! Experiment to find fringe width using biprism Icon_biggrin