Total Internal Reflection Video Lessons

Concept

# Problem: Canola oil is less dense than water, so it floats on water, but its index of refraction is 1.47, higher than that of water. When you are adding oil and water to a bottle to make salad dressing, you notice a silvery reflection of light from the boundary between the oil and water.What is the critical angle for light going from the oil into the water?

###### FREE Expert Solution

From Snell's law, we can get critical angle by setting the angle of refraction at 90°.

Therefore, we have:

$\overline{)\begin{array}{rcl}{\mathbf{\eta }}_{\mathbf{i}}{\mathbf{sin\theta }}_{\mathbf{C}}& {\mathbf{=}}& {\mathbf{\eta }}_{\mathbf{t}}\mathbf{sin}\mathbf{\left(}\mathbf{90}\mathbf{°}\mathbf{\right)}\end{array}}$

###### Problem Details

Canola oil is less dense than water, so it floats on water, but its index of refraction is 1.47, higher than that of water. When you are adding oil and water to a bottle to make salad dressing, you notice a silvery reflection of light from the boundary between the oil and water.

What is the critical angle for light going from the oil into the water?