A mixture of Yellow light of wavelength 580 nm and blue light of wave length 450 nm is incident normally on an air film of thickness $2.9 imes 10^{-4} \mathrm{~mm}$. The colour of reflected light is

Question

A mixture of Yellow light of wavelength 580 nm and blue light of wave length 450 nm is incident normally on an air film of thickness $2.9 	imes 10^{-4} \mathrm{~mm}$. The colour of reflected light is

Aicharya · Accepted Answer

Using the bragg's law the path difference for first reflected light,

The thickness of film is $d = 2.9 \times 10^{- 4} mm$

The angle between the incident ray and film is $90 °$

Therefore,

$n λ = 2 d \sin θ λ = 2 d \sin θ = 2 \times 2.9 \times 10^{- 4} mm \times \sin 90 ° λ = 5.8 \times 10^{- 7} m = 580 nm$

The wavelength obtained is corresponding to Yellow light.

Thus, the colour of reflected light is, Yellow.

A mixture of Yellow light of wavelength 580 nm and blue light of wave length 450 nm is incident normally on…

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