Question

What is the minimum thickness of a nonreflecting film coating (n = 1.30) on a glass lens (n = 1.50) for wavelength 500 nm?

Answer 1

The thickness of the non-reflective coating layer is 9.62 x 10¯⁸ m or 96.2 nm.

From the question we know that :

n = 1.30

λ = 500nm = 5 x 10¯⁷m

The non-reflective coating system is applied on glass and the refractive index of that system should be  nair < ncoating < nglass. The light travels across the air and is refracted by coating film and then refracted again by the glass. For preventing the light got reflected by glass, the thickness of the layer should obey this equation :

2nt = λ/2

t is the thickness of the layer, λ is the wavelength and n is the refractive index of the film.

By substituting the following equation we get

2nt = λ/2

t = 1/4 . ( λ / n )

t = 1/4 . ( 5 x 10¯⁷ / 1.3)

t = 9.62 x 10¯⁸ m

Hence, the thickness of the non-reflective coating layer is 9.62 x 10¯⁸ m or 96.2 nm.

Find out more on non-reflective coating at: brainly.com/question/17205515

#SPJ4