Answer:
The thickness of the oil slick is 
Explanation:
Given that,
Index of refraction = 1.28
Wave length = 500 nm
Order m = 1
We need to calculate the thickness of oil slick
Using formula of thickness

Where, n = Index of refraction
t = thickness
= wavelength
Put the value into the formula



Hence, The thickness of the oil slick is 
I would say Conduction because you are touching the cookie sheet, even though it is hot (so heat) you are physically touching it so it would not be radiation
Density =mass/volume
density= (0.044kg/(11 x10^-6)
4000kg/m^3