13. ssm The drawing shows a coin resting on the bottom of a beaker filled with an unknown liquid. A ray of light from the coin travels to the surface of the liquid and is refracted as it enters into the air. A person sees the ray as it skims just above the surface of the liquid. How fast is the light traveling in the liquid?

 

w1373

 

Snell’s law gives us

 

We are given qair is 90°.  The angle of incidence in the unknown is shown on the sketch below

So we can use tangent function to get qi

 

 

 

 

 

 

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This page last updated on July 1, 2018