A thin film of thickness t and index of refraction 1.33 coats a glass with index of refraction 1.50.Which of the following thickness t will not reflect normally incident light with wavelength 640 nm in air?

120nm,240nm,300nm,480nm

(ans is 120 nm)

Dear student,

This is a simple formula based problem based on introduction of thin film..

The correct answer i got is 120 nm..

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