An oil tanker spills a large amount of oil (nn = 1.45) into the sea (nn = 1.35). (a) If you look down onto the oil spill from overhead, what predominant wavelength of light do you see at a point where the oil is 380 nmnm thick? What color is the light? (b) In the water under the slick, what visible wavelength (as measured in air) is predominant in the transmitted light at the same place in the slick as in part (a)?

Explanation:

The problem is based on interference in thin films .

for constructive interference the condition is as follows

2μd = ( 2n+1 ) λ/2  , μ is refractive index of oil , t is thickness , λ is wavelength of light.

2 x 1.45 x 380 nm = ( 2n+1 ) λ/2

= 1102 nm = odd multiple of  λ/2

if we take odd multiple as 3

λ = 734.66 nm which is the wavelength of red light .

So from above red light will be visible .

b )

when viewed from below , in the transmitted light , the condition for constructive interference is as follows

2μd = n λ

2 x 1.45 x 380 = n λ

1102 = n λ

when n = 2

λ = 501 nm

This is wavelength of green colour .

So from water side green colour will be visible.

your answer is, orbit around the nucleus