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Question
If Young's double slit experiment is performed in water, _________________ .
Options
the fringe width will decrease
the fringe width will increase
the fringe width will remain unchanged
there will be no fringe
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Solution
the fringe width will decrease
As fringe width is proportional to the wavelength and wavelength of light is inversely proportional to the refractive index of the medium,
Here,
\[\lambda_M = \lambda/\eta\]
\[ \lambda_M = \text{wavelength in medium}\]
\[\lambda = \text{wavelength in vacuum}\]
\[\eta = \text{refractive index of medium}\]
Hence, fringe width decreases when Young's double slit experiment is performed under water.
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