Answer the following questions. Some of the answers are found in the “Check Your Understanding” sections of the tutorial. For these questions you must either show your work or explain your reasoning.

Lesson 1: Reflection and Its Importance
The Role of Light to Sight

1. Explain this picture. How could this explain why outer space is black even though it is full of stars?


2. Can you see the path the laser beam follows? Where can this laser light be seen? Why?

Lesson 1: Reflection and Its Importance
The Line of Sight

The following diagrams depict some ideas about how light might travel from an object location to an eye location when viewed the image of the object is viewed in a mirror. Comment on the incorrectness of the following diagrams. Discuss what makes them incorrect.

Lesson 1: Reflection and Its Importance
The Law of Reflection

1. State the Law of Reflection in words and draw a diagram with the incident and relfected rays and the angles of incidence and reflection labeled.

2. Consider the diagram below. Which one of the angles (A, B, C, or D) is the angle of incidence? Which one of the angles is the angle of reflection?

3. A ray of light is incident towards a plane mirror at an angle of 30-degrees with the mirror surface. What will be the angle of reflection?

4. Why do windows of distant houses appear to reflect the sun only when rising or setting? Use the diagram below to explain, drawing appropriate light rays on the diagram.

5. A ray of light is approaching a set of three mirrors as shown in the diagram. The light ray is approaching the first mirror at an angle of 45-degrees with the mirror surface. Trace the path of the light ray as it bounces off the mirror; continue tracing the ray until it finally exits from the mirror system. How many times will the ray reflect before it finally exits?

Lesson 1: Reflection and Its Importance
Specular vs. Diffuse Reflection

1. Draw a diagram showing specular reflection from a smooth surface.




2. Draw a diagram showing diffuse reflection from a rough surface.




3. If a bundle of parallel incident rays undergoing diffuse reflection follow the law of reflection, then why do they scatter in many different directions after reflecting off a surface?



4. Is it easier to read from pages of a book which are rough or from pages which are smooth and glossy? Explain your answer.