Question

Determine the smallest thickness of the film for which reflected green light of wavelength 540 nm interfere destructively. Express your answer with the appropriate units.

Answer 1

Answer:

Explanation:

Given

Wavelength of green light $\lambda =540\ nm$

For destructive interference by reflection the path difference is an integral multiple of wavelength so

$t=\frac{\lambda '}{2}$

where $\lambda '=\frac{\lambda }{n}$

n=refractive index of medium

suppose water is the medium

so

$n=\frac{4}{3}$

$t=\frac{540\times 3}{4\times 2}$

$t=202.5\ nm$