# Ray Optics: Refraction and Lenses

## Refraction and Lenses: Audio Guided Solution

#### Problem 16:

During a demonstration of fiber optics, Mr. H uses an acrylic light pipe to demonstrate total internal reflection for light as it navigates its way through a curved medium, entering at one end and exitting at the other with very little loss of light along the way.
a. If the acrylic has an index of refraction of 1.48, then determine its critical angle when surrounded by air.
b. Determine the critical angle of the acrylic light pipe when surrounded by water (n=1.33).

## Habits of an Effective Problem Solver

• Read the problem carefully and develop a mental picture of the physical situation. If necessary, sketch a simple diagram of the physical situation to help you visualize it.
• Identify the known and unknown quantities and record them in an organized manner. Equate given values to the symbols used to represent the corresponding quantity - e.g., do = 24,8 cm; di = 16.7 cm; f = ???.
• Use physics formulas and conceptual reasoning to plot a strategy for solving for the unknown quantity.
• Identify the appropriate formula(s) to use.
• Perform substitutions and algebraic manipulations in order to solve for the unknown quantity.