Q: What is the law of reflection?

The angle of reflection equals the angle of incidence: $$\theta_r = \theta_i$$

Question 1

Which of the following best describes a light ray in the ray model of light?

Accepted Answer

A line in the direction along which light energy flows.

Question 2

A camera obscura forms an inverted image of a tree on its back wall. If the distance from the aperture to the image is $$d_i$$ and the distance from the aperture to the object is $$d_o$$, what is the relationship between the image height $$h_i$$ and the object height $$h_o$$?

Accepted Answer

$$\displaystyle \frac{h_i}{h_o} = \frac{d_i}{d_o}$$

Question 3

Which of the following is an example of a self-luminous object?

Accepted Answer

A lightbulb that is turned on.

Question 4

What is the law of reflection?

Accepted Answer

The angle of reflection equals the angle of incidence: $$	heta_r = 	heta_i$$

Question 5

A laser beam passes from air ($$n_1 = 1.00$) into glass (n_2$ = 1.50) at an $$angle. According to Snell's Law, what happens to the direction of the beam?

Accepted Answer

It bends toward the normal.

Question 6

Which of the following best describes specular reflection?

Accepted Answer

Reflection by a flat smooth object.

Question 7

A virtual image is formed when:

Accepted Answer

Rays appear to diverge from a point behind the mirror.

Question 8

A person stands in front of a plane mirror. If the top half of the mirror is covered, what will the person see?

Accepted Answer

The full image of themselves.

Question 9

Which of the following statements about diffuse reflection is correct?

Accepted Answer

It causes reflected rays to leave in many random directions.

Question 10

A ray of light passes from water ($$n = 1.33) $$into air ($$n = 1.00) at an $$angle greater than the critical angle. What phenomenon occurs?

Accepted Answer

Total internal reflection.

Question 11

Which of the following is the correct thin lens equation relating object distance $$s$$, image distance $$s'$$, and focal length $$f$$?

Accepted Answer

$$\displaystyle \frac{1}{f} = \frac{1}{s} + \frac{1}{s'}$$

Question 12

A converging lens is used to focus sunlight to start a fire. Why is a converging lens required?

Accepted Answer

It focuses parallel rays to a single point, increasing intensity.

Question 13

A fish in an aquarium looks out at a cat through the flat side of the tank. To the fish, the cat appears:

Accepted Answer

Closer than the actual distance.

Question 14

Which of the following is true for the focal length $$f of a $$converging lens?

Accepted Answer

It is the distance at which parallel light rays are focused.

Question 15

A lens produces a sharply focused, inverted image on a screen. What will you see on the screen if the lens is removed?

Accepted Answer

No image at all.

Question 16

Which of the following best describes the function of optical fibers in modern technology?

Accepted Answer

They use total internal reflection to transmit light signals over long distances.

Question 17

A paraxial ray is:

Accepted Answer

A ray that moves nearly parallel to the optical axis.

Question 18

Which of the following is NOT a reason why optics is important in modern life?

Accepted Answer

It is only relevant for studying sound waves.

Question 19

A real image is formed by a lens when:

Accepted Answer

Rays actually converge at the image location.

Question 20

Which of the following best describes the difference between specular and diffuse reflection?

Accepted Answer

Specular reflection produces clear images, while diffuse reflection scatters light in many directions.

Ray Optics: Fundamentals and Applications

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