What is the thinnest film of a coating with n = 1.38 on glass (n=1.52) for which destructive interference of the red component (640 nm) of an incident white light beam in air can take place by reflection?

115.94 nm ≅ 116 nm

Explanation:

so,

2nt = (m+0.5) λ

t = ₓ λ

t =(m+0.5)ₓ

For minimum value of "t" ,"m" should be 0

t =

t = 115.94≅ 116nm

potential energy is directly proportional to height.

more height = more potential energy.

greatest increase in height = greatest increase in potential energy

where are the points with the greatest increase in height ?

has to be c-e or d-e .

there are no correct statementd on the list of choices you provided.