White light is incident normally on a glass plate (in air) of thickness `500 nm` and refractive index of `1.5`. The wavelength (in `nm`) in the visibl

Monjur Alahi

White light is incident normally on a glass plate (in air) of thickness `500 nm` and refractive index of `1.5`. The wavelength (in `nm`) in the visible region `(400 nm-700nm)` that is strongly reflected by the plate is:
A. `450`
B. `600`
C. `400`
D. `500`


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Salim Ahmed Kawsar

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Correct Answer - B
For strong reflection.
`2mut=(lambda)/(2),(3lambda)/(2),(5lambda)/(2).....rArr lambda=4mut,(4mut)/(3),(4mut)/(5),(4mut)/(7).....`
`rArr 3000 nm. 1000 nm, 600 nm, 333 nm.`
`rArr` only option is `600 nm`.

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