Chapter 7

For specular reflection, what is the situation with an angle of incidence of (a) \(0^{\circ}\) and (b) \(90^{\circ} ?\)

Dutch painter Vincent van Gogh was emotionally troubled and once cut off part of his own ear. His Self Portrait with Bandaged Ear (1889) is shown in \(\bullet\) Fig. 7.38. Which ear did he cut? (Hint: How do you paint a self- portrait?)

When you walk toward a full-length plane mirror, what does your image do? How fast does the image move? Is the image in step with you?

How long does the image of a 12 -in. ruler appear in a plane mirror? Does it depend on the distance the ruler is from the mirror?

Is there refraction for incident angles of (a) \(0^{\circ}\) and (b) \(90^{\circ} ?\)

From the Earth, stars are seen to "twinkle." What does an astronaut see from the International Space Station (ISS) orbiting the Earth?

For any substance, the index of refraction is always greater than 1. Why?

Does atmospheric refraction affect the length of the day? Would the daylight hours be longer or shorter if the Earth had no atmosphere?

What relationships exist between the center of curvature, the focal point, the focal length, and the vertex of a spherical mirror?

Distinguish between real images and virtual images for spherical mirrors.

Explain when real and virtual images are formed by (a) a convex mirror and (b) a concave mirror.

What happens to a light ray that passes through the focal point at an angle to the optic axis of a concave mirror?

When a light ray parallel to the optic axis is reflected from a concave mirror, where does it go?

Why are the back surfaces of automobile headlights curved?

What type of mirror would be used for the solar heating of water?

Where is a diverging lens thickest?

A magnifying glass is a convex lens. Sunlight can be focused to a small spot using such a lens. What is the small spot an image of? Why are holes burnt in pieces of paper or leaves when the small spot is focused on them?

Why do some people wear bifocal or trifocal eyeglasses?

Give two examples of practical applications of polarization.

How could you use polarization to distinguish between longitudinal and transverse waves?

How can it be shown or proved that light is diffracted?

Why do sound waves bend around everyday objects, whereas the bending of light is not generally observed?

Which are more easily diffracted by ordinary objects, AM radio waves or FM radio waves? Explain why.

Describe the interference of two wave pulses with different amplitudes if they are (a) in phase and (b) completely out of phase.

What optical phenomenon causes soap bubbles and oil slicks to show colorful displays?