Deck 9: Optics

Question 1

Light is a transverse wave.

Answer 1

True

Question 2

The path of a light ray through a refracting surface is reversible.

Answer 2

True

Question 3

Light goes slower through glass than through air.

Answer 3

True

Question 4

When light passes through two or more narrow slits, an alternating dark and bright pattern is observed on a screen because of interference.

Question 5

A light ray bends when it goes from one medium to another because of diffraction.

Question 6

The colors you see with a prism result because the light is diffracted.

Question 7

Optical fibers work because of dispersion of light.

Question 8

Liquid crystal displays make use of interference of light.

Question 9

Blue light travels more slowly through glass than red light does.

Question 10

Certain types of sunglasses are very effective at diminishing light reflected from surfaces because of polarization.

Question 11

Your eye's iris changes the size of your pupil to adjust the amount of light that enters your eye.

Question 12

Astigmatism is due to too flat a cornea.

Question 13

You can see your image in a mirror because of diffuse reflection.

Question 14

Light spreads out when it passes through a narrow slit because of interference.

Question 15

You see colors in a rainbow because of diffraction.

Question 16

Dispersion results because the speed of light in a transparent medium varies with frequency.

Question 17

A light ray can pass through a diverging lens without being deflected.

Question 18

You do not see your image when you look at a flat rough aluminum surface because of specular reflection.

Question 19

When you look into a pool of water, the depth looks less than it actually is because the light is dispersed.

Question 20

The lens in your eye and the cornea both contribute to image formation.

Question 21

Halos are caused by hexagonal ice crystals in the upper atmosphere.

Question 22

A converging lens always forms an object's image at the focal point of the lens.

Question 23

The Hubble Space Telescope has been repaired.

Question 24

LCDs operate on the principle of refraction through glass.

Question 25

The speed of light in any transparent medium is the same as the speed of light in a vacuum.

Question 26

An EM wave with a wavelength of 500 nm will be visible.

Question 27

You look at yourself in a plane mirror. If you move away from the mirror and look at yourself again, you now see more of yourself.

Question 28

A diverging lens is thicker at the center than the edges.

Question 29

A person looking through eyeglasses sees real images.

Question 30

A magnifying glass with focal length 15 cm is placed 10 cm above a stamp. The image of the stamp is located 30 cm above the magnifying glass.

Question 31

The lens formula relating the image distance, p , to the focal length, f , and object distance, s , is
The magnification of a lens is
A movie projector is equipped with a 0.5-m focal length lens that is positioned 0.505 m in front of the film. The distance in front of the lens that a screen must be placed for an image to be in focus is 50.5 m.

Question 32

The lens formula relating the image distance, p , to the focal length, f , and object distance, s , is
The magnification of a lens is
The magnification of the magnifying glass in the previous problem is -3.

Question 33

The ideal shape for the primary mirror of a telescope is concave parabolic.

Question 34

A one-way mirror works because its surfaces are half-silvered.

Question 35

A convex mirror will allow you to see large areas normally hidden from your view.

Question 36

An image seen projected on a screen by a single lens is always inverted.

Question 37

The lens formula relating the image distance, p , to the focal length, f , and object distance, s , is
The magnification of a lens is
For the projector in the previous problem, the image is 10 times as large as the object.

Question 38

Diverging lenses have negative focal lengths.

Question 39

In the atmosphere, the intensity of scattered sunlight of longer wavelength is greater than that of shorter wavelength.

Question 40

A curved mirror that produces an enlarged image will also have a greater field of view than a plane mirror.

Question 41

In order to see a rainbow, the Sun must be directly in front of you.

Question 42

If you see a rainbow near the time of sunset, where in the sky will the rainbow be?

A) overhead
B) toward the eastern horizon
C) toward the western horizon
D) toward the northern horizon
E) toward the southern horizon

Question 43

Which of the following is not involved in the formation of a rainbow?

A) interference
B) dispersion
C) internal reflection
D) refraction

Question 44

You see colors in a rainbow because of

A) interference.
B) diffraction.
C) specular reflection.
D) dispersion.
E) polarization.

Question 45

Light spreads out when it passes through a narrow slit because of

A) interference.
B) diffraction.
C) specular reflection.
D) diffuse reflection.
E) polarization.

Question 46

When light passes through two or more narrow slits, an alternating dark and bright pattern is observed on a screen because of

A) interference.
B) diffraction.
C) specular reflection.
D) diffuse reflection.
E) polarization.

Question 47

You can see your image in a mirror because of

A) interference.
B) diffraction.
C) specular reflection.
D) diffuse reflection.
E) polarization.

Question 48

Optical fibers work because of

A) interference.
B) diffraction.
C) total internal reflection.
D) diffuse reflection.
E) polarization.

Question 49

What is meant by the "normal" to a surface?

A) a line perpendicular to the surface at a given point
B) the angle between the surface and the light ray
C) a line parallel to the surface at a given point
D) the direction of a reflected ray

Question 50

Which of the lines in the figure represents the normal to the surface at point P?

A) 1
B) 2
C) 3
D) 4
E) none of the above

Question 51

Why are optical fibers important for communication?

A) They can carry thousands of times the information that wires can.
B) Light goes faster than electricity.
C) They carry digital information. Wires can't carry digital information.
D) all of the above

Question 52

Thin film interference is responsible for the colors of

A) bird feathers.
B) gasoline spills.
C) soap bubbles.
D) all of the above.

Question 53

The colors of objects we see by reflected light are due to

A) interference.
B) selective absorption.
C) specular reflection.
D) diffuse reflection.

Question 54

Which angle is the angle of incidence for the light ray shown approaching the plane mirror?

A) 60°
B) 30°
C) neither
D) either

Question 55

You do not see your image when you look at a flat rough aluminum surface because of

A) interference.
B) diffraction.
C) specular reflection.
D) diffuse reflection.
E) polarization.

Question 56

A helium neon laser generates light of 632.8-nm wavelength. What color is that?

A) blue
B) yellow
C) red
D) green

Question 57

Certain types of sunglasses are very effective at diminishing light reflected from surfaces because of

A) interference.
B) diffraction.
C) specular reflection.
D) diffuse reflection.
E) polarization.

Question 58

Liquid crystal displays make use of

A) interference.
B) diffraction.
C) specular reflection.
D) diffuse reflection.
E) polarization.

Question 59

According to the law of reflection, a light ray striking a mirror at an angle of incidence of 30 degrees will leaves the mirror at an angle of

A) 60 degrees.
B) 30 degrees.
C) less than 30 degrees.
D) none of the above.

Question 60

The sky is blue due to air molecules scattering sunlight in all directions.

Question 61

The ideal shape for the primary mirror of a telescope is

A) concave circular.
B) convex circular.
C) concave parabolic.
D) convex parabolic.
E) plane.

Question 62

The variation of the speed of light in a transparent medium with frequency results in

A) interference.
B) diffraction.
C) dispersion.
D) diffuse reflection.
E) polarization.

Question 63

In optics, what is meant by an "interface?"

A) optically connecting one computer to another
B) using the image created by one lens as the object for another lens
C) when the crest of one wave lines up with the trough of another wave
D) none of the above

Question 64

In this figure a light ray travels between air and glass. Which way did the light ray go?

A) from the air into the glass
B) from the glass into the air
C) either A or B.
D) None of the above-this depicts an impossible situation.

Question 65

An object is 50 cm in front of a plane mirror. Its image will be located

A) 50 cm in front of the mirror.
B) at the mirror's surface.
C) 50 cm behind the mirror.
D) 25 cm in front of the mirror.
E) 25 cm behind the mirror.

Question 66

A light ray bends when it goes from one medium to another because of

A) interference.
B) diffraction.
C) specular reflection.
D) refraction.
E) polarization.

Question 67

What is meant by the term "plane mirror?"

A) not an unusual mirror
B) a flat mirror
C) a horizontal mirror
D) none of the above

Question 68

Upon entering a medium in which the speed of light is 1.5 × 10⁸ m/s from a medium in which the speed of light is 2 × 10⁸ m/s, an oblique light ray will be _____________ the normal to the interface between the two media.

A) bent away from
B) bent toward
C) travel along
D) remain undeviated with respect to

Question 69

In air a light source emits a wavelength of 630 nm. Under water the wavelength of this light will be

A) 630 nm.
B) less than 630 nm.
C) more than 630 nm.
D) unpredictable.

Question 70

What makes pink ink pink?

A) refraction
B) selective absorption
C) dispersion
D) none of the above

Question 71

The type of mirror that will allow you to see large areas normally hidden from your view is

A) concave.
B) convex.
C) plane.
D) half-silvered.
E) Polaroid.

Question 72

A one-way mirror works because of

A) interference.
B) diffraction.
C) its surfaces being half-silvered.
D) dispersion.
E) polarization.

Question 73

New telescopes are using "adaptive optics."  What is that?

A) using parabolic instead of spherical mirrors
B) using computer image processing to enhance images
C) building mirrors in hexagonal segments
D) continually adjusting the mirror's shape during observations

Question 74

The sky is blue because of

A) interference.
B) diffraction.
C) scattering.
D) dispersion.
E) polarization.

Question 75

Parallel light rays from a distant object strike the surface of a concave mirror. After reflecting from the mirror's surface, the rays will converge at

A) the mirror's focal point.
B) a point beyond the mirror's focal point.
C) a point nearer than the mirror's focal point.
D) none of the above.

Question 76

Diverging light rays from a nearby object (a few focal lengths away from the mirror) strike the surface of a concave mirror. After reflecting from the mirror's surface, the rays will converge at

A) the mirror's focal point.
B) a point beyond the mirror's focal point.
C) a point nearer than the mirror's focal point.
D) none of the above.

Question 77

When you look into a pool of water, the depth looks less than it actually is because of

A) interference.
B) diffraction.
C) specular reflection.
D) refraction.
E) polarization.

Question 78

Rank the following media in order according to the speed of light in them, from slowest to fastest: vacuum, air, water and glass.

A) air, water, glass, vacuum
B) glass, air, water, vacuum
C) water, glass, air, vacuum
D) glass, water, air, vacuum
E) none of the above

Question 79

The primary mirror in an astronomical telescope must be a

A) half-silvered mirror.
B) convex mirror.
C) concave mirror.
D) plane mirror.

Question 80

You see colors with a prism because of

A) interference.
B) diffraction.
C) specular reflection.
D) dispersion.
E) polarization.