# #

Turpentine is a liquid extracted from pine tree resin and used to remove paint from paint brushes. Being less dense than water it will float on the surface of water if you rinse it off your hands after using it.

## Part 1#

A 14 nm thick thin film of turpentine ($$n\_{turpentine}=1.47$$) on top of water ($$n\_{water}=1.33$$) will:

• Reflects almost all light hitting it since light reflects with the same phase from both surfaces and the path length difference is much less than the wavelength of the visible light.

• will appear blue since ($$λ_{blue}$$)/2 = $$28 nm$$

• Will appear blue since ($$λ_{blue}$$)/(2*$$n_{turpentine}$$)= $$28 nm$$

• Will look like a normal water surface since both water and turpentine are transparent.

• Will reflect almost no light as light reflects with different phases from each surface and the path length difference is much less than the wavelength of visible light.