When light passes from vacuum (index of

refraction n = 1) into water (n = 1.333),

A. the wavelength increases and the frequency is

unchanged

B. the wavelength decreases and the frequency is

unchanged

C. the wavelength is unchanged and the frequency

increases

D. the wavelength is unchanged and the frequency

decreases

E. both the wavelength and the frequency change

33.1

I II III

25

35

25

o

40o

o o

A ray of light passes through 3 regions labeled I,

II, and III, as shown.

How do the indices of refraction of regions I and

III compare? A) nI > nII B) nI < nIII C) nI = nIII

D) Impossible to tell

35-2

glass

air

A light ray inside glass is totally internally

reflected from an air-glass interface as shown.

The air surrounding the glass is replaced with

water. With the same light ray in the glass, the

total internal reflection will now...

A) definitely not occur.

B) definitely occur.

C) not enough information to know

35-4

Light passes from a medium of index of

refraction na into a second medium of index of

refraction nb. In order for total internal reflection

to occur, it must be true that

A. na > nb and the incident angle qa is greater than

the critical angle

B. na > nb and the incident angle qa is less than

the critical angle

C. na < nb and the incident angle qa is greater than

the critical angle

D. na < nb and the incident angle qa is less than

the critical angle

33-3

Pink

Green

Yellow air, n =1 glass, n =1.5

A ray of light passes thru a sheet of glass which is thick at the

bottom and thin at the top. Which way is the ray traveling

after it has passed through the glass?

A) bent toward the thin end

B) Undeviated

C) bent toward the thick end

35-3

A

B

C

D) n3 > n2 > n1

E) n1 = n2 = n3

A light wave travels through three transparent

materials of equal thickness. Rank is order, from the

largest to smallest, the indices of refraction n1, n2, and

n3.

A. n2 > n1 > n3

B. n3 > n1 > n2

C. n1 > n2 > n3

Optics 1

A fish swims below the surface of the water

at P. An observer at O sees the fish at

A) a greater depth than it really is.

B) the same depth.

C) a smaller depth than it really is.

Optics 4

A converging lens focuses the light from a

nearby point source onto an image, as shown.

The "focal point" of a lens is the point on the

optic axis, one focal length f from the lens.

Where is the focal point of this lens?

image object

Pink Yellow Green A B C

36-4

A converging lens has a focal length f = 20cm

when it is in air. The lens is made of glass with

index of refraction nglass = 1.6. When the lens is

placed in water (nwater = 1.33), the focal length of

the lens is..

A) Unchanged.

B) greater, f > 20 cm.

C) smaller, f < 20cm

36-1

A lens produces a sharply-

focused, inverted image on a

screen. What will you see on

the screen if the lens is

removed?

A. The image will be as it was, but much dimmer.

B. The image will be right-side-up and sharp.

C. The image will be right-side-up and blurry.

D. The image will be inverted and blurry.

E. There will be no image at all.

Optics 2

Two point sources of light are imaged onto a screen by

a converging lens as shown. The images are labeled

1 and 2. A mask is used to cover up the left half of the

lens, as shown. What happens to the images on the

screen when the mask is inserted over the left half the

lens? screen

lens

mask

1 2

A) Image 1 vanishes

B) Image 2 vanishes

C) Something else

happens

36-2

Which of these

actions will move

the image point

P´ further from

the boundary?

A. Increase the radius of curvature R.

B. Increase the index of refraction n.

C. Increase the object distance s.

D. Decrease the radius of curvature R.

Optics 3

f f

object

The image formed by the lens is

A) Real, non-inverted

B) Real, inverted

C) Virtual, non-inverted

D) Virtual , inverted

E) no image is formed

Optics 4

image

object

(virtual!)

dodi

An object is placed closer to a magnifying glass than

the focal length. What are the signs of the focal length

f, the object distance do, and the image distance di?

A) f > 0, do > 0, di < 0. B) f < 0, do > 0, di < 0.

C) f > 0, do < 0, di > 0. D) f > 0, do > 0, di > 0.

36-6

An object is placed is placed near a diverging

lens, but the object is closer to the lens than

the absolute value of the focal length of the

lens. The magnitude of the image distance,

compared to the object distance, is ...

A) Smaller (di<do)

B) Larger (di>do)

C) Same (di=do)

36-5b

An object is placed is placed near a diverging

lens, but the object is closer to the lens than

the absolute value of the focal length of the

lens. The image formed is..

A) Real

B) Virtual

C) there is no image.

36-5

A person who is "near-sighted“ can’t focus on faraway

objects because the curvature of the person's eye-

lens is too great. This causes parallel rays to bend

too much and focus in front of the retina. The person

sees a fuzzy patch of light rather than a sharp point.

f too short This person needs eyeglasses with lenses that are

A) converging B) diverging

C) either converging or diverging, depending on much

correction is needed.

36-7

Which of the following changes its focal

length when it is immersed in water?

A. a concave mirror

B. a convex mirror

C. a diverging lens

D. all of the above

E. none of the above

A concave mirror with a radius of curvature

of 20 cm has a focal length of

A. 40 cm.

B. 20 cm.

C. 10 cm.

D. 5 cm.

E. answer depends on the index of

refraction of the air around the mirror

An object is placed 1.5 m away from a

concave mirror of focal length +1.0 m. The

image formed by the mirror is

A. real and larger than the object.

B. real and smaller than the object.

C. real and the same size as the object.

D. virtual and larger than the object.

E. virtual and smaller than the object.