Question

Please help me with this question :

A soap bubble has the index of refraction n = 1.33. There is air both inside and outside

the bubble.

a/ What wavelength (in air) of visible light is most strungly reflected from a point on a soap bubble where

its wall is 290 nm thick? To what color does this correspond?

b/ Repeat part a/ for a wall thickness of 340 nm. What is your observation about the two answers a/ and b/?

Answer 1

• 514.27 ( wavelength )

the color is green

• 602.93 nm ( orange color )

the observation is that there is a change of visible color

Step-by-step explanation:

A) wavelength of visible light that is most strongly reflected from a point on a soap

refraction n = 1.33

wall thickness (t) = 290 nm

2nt = (2m +1 ) ∝/2 -----equation 1

note when m = 0

therefore ∝ = 4nt/ 1 = 4 * 1.33 * 290 = 1542.8nm we will discard this

when m = 1

equation 1 becomes

∝ = 4nt/3 =( 4 * 1.33 * 290) / 3 = 1542.8 / 3 = 514.27 ( wavelength )

the color is green

B) the wavelength when the wall thickness is 340 nm

∝ = 4nt / 2m +1

where m = 1

∝ = (4 * 1.33 * 340 ) / 3 = 1808.8 / 3 = 602.93 nm ( orange color )

the observation is that there is a change of visible color