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.

Explanation:

Given

Wavelength of green light

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

where

n=refractive index of medium

suppose water is the medium

so

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach