Lesson: Refracted Light Ray Paths Physics • 9th Grade

In this lesson, we will learn how to analyze refraction that involves multiple boundaries, multiple rays, and boundaries at arbitrary angles to each other.

Lesson Plan

Students will be able to

determine the paths of light rays that are refracted at multiple boundaries that may be at arbitrary angles to each other,
determine the differences between paths of light rays that move through the same object from different initial positions and/or traveling in different directions,
apply Snell’s law to light rays that pass through prisms.

Lesson Worksheet

Q1:

A light ray traveling in air with a refractive index of 1.0 is refracted by the prism shown in the diagram, which is made of a substance with a refractive index of 1.6. What is the measure of the angle ?

Q2:

Two light rays travel through air and are incident on a layer of glass, as shown in the diagram. The rays pass through the layer of glass and arrive at the same point, from which they pass into a layer of plastic. Two rays emerge from the plastic layer. Does the ray that follows the path of incident ray I follow the path of emergent ray I or emergent ray II?

Q3:

Two rays that initially travel through air that has a refractive index of 1.0 are incident on different sides of a right-angled triangular prism made of a substance that has a refractive index of 1.45.

What is the angle between the emergent ray that follows the path of incident ray I and the normal to the surface from which it emerges?

What is the angle between the emergent ray that follows the path of incident ray II and the normal to the surface from which it emerges?