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:

Options

A. 450
B. 600
C. 400
D. 500

Answer

B

Explanation

For strong reflection,
`2 mu t = ……….. (lambda)/(2), (3lambda)/(2), (5 lambda)/(2)`
`rArr lambda = 4 mu t, ………… (4 mu t)/(3), (4 mu t)/(5), (4 mu t)/(7)`
`rArr` 3000 nm. 1000 nm, 600 nm, 430 nm, 333 nm.
`rArr` Only option is 600 nm.