Question

While finely sanding down some fluorite to use as a center stone on a necklace, a thin layer of oil (n = 1.299) is left on the fluorite.  When seen in the full visible spectrum (400 - 700 nm) of sunlight, the fluorite reflects back all but the wavelength 650 nm.  

a.  What are the two smallest thicknesses of the oil?

b.  Was this light interfering constructively or destructively?  

c.  How many phase changes did the light reaching their eye experience?  

d.  Complete the diagram showing the composition of each layer and explicitly where any phase changes happened.

Answer 1