What is the smallest thickness d of a soap film (n= 1.42) that gives a maximal r
ID: 1490050 • Letter: W
Question
What is the smallest thickness d of a soap film (n= 1.42) that gives a maximal reflection if illuminated by a green light (Wavelength=700 nm)? (Use the interference condition for the light reflected from the top and bottom sides of the film, taking into account the possible wavelength/2 phase change upon reflection). What is the smallest thickness d of a soap film (n= 1.42) that gives a maximal reflection if illuminated by a green light (Wavelength=700 nm)? (Use the interference condition for the light reflected from the top and bottom sides of the film, taking into account the possible wavelength/2 phase change upon reflection).Explanation / Answer
For constructive interference
thickness tmin =/4n
where refractive index of film n =1.42
wavelength =700 nm
substitute the given data in above equation we get
t =123.24 nm