The width of fringe is 2 mm on the screen in a double slits experiment for the light of wavelength of 400 nm. The width of the fringe for the light of wavelength 600 nm will be:
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Question

The width of fringe is 2 mm on the screen in a double slits experiment for the light of wavelength of 400 nm. The width of the fringe for the light of wavelength 600 nm will be:

G1 Physics · Accepted Answer

For fixed slit separation and screen distance, fringe width β=λD/d is directly proportional to wavelength. Thus β₂=2 mm×(600/400)=3 mm. Option C.