Physics Exam #3

Front 1

Consider two diffraction gratings with the same slit separation. The only difference between the two gratings is that one grating has 5 slits and the other 10 slits. Both gratings are illuminated with a beam of the same monochromatic light. Which of the following statements are true?

Back 1

The grating with 10 slits produces better-defined (narrower) peaks.

Both gratings produce the same separation between peaks.

Front 2

In a double-slit experiment, two beams of coherent light traveling different paths arrive on a screen some distance away. What is the path difference between the two waves corresponding to the third bright band out from the central bright band?

Back 2

The path difference between the two waves is three wavelengths.

Front 3

A single-slit diffraction pattern is formed on a distant screen. If the distance from the slit to the screen is doubled, by what factor will the width of the central bright fringe on the screen change? Assume the angles involved remain small.

Back 3

The width of the central bright fringe will be twice its original size.

Front 4

Two beams of coherent light travel different paths, arriving at point P. If the maximum destructive interference is to occur at point P, what should be the path difference between the two waves?

Back 4

The path difference between the two waves should be one-half of a wavelength.

Front 5

In a single-slit diffraction experiment, the width of the slit through which light passes is reduced. What happens to the width of the central bright fringe in the resulting diffraction pattern?

Back 5

It becomes wider.

Front 6

A single-slit diffraction pattern is formed on a distant screen. Assuming the angles involved are small, by what factor will the width of the central bright spot on the screen change if the wavelength of the illuminating light is doubled?

Back 6

It will double.

Front 7

If you stand in front of a convex mirror, at the same distance from it as its radius of curvature,

Back 7

you will see your image and you will appear smaller than you.

Front 8

When glasses (or contact lenses) are used to correct nearsightedness, where should the corrective lens form an image of an object located at infinity in order for the eye to form a clear image of that object?

Back 8

The lens should form the image at the far point.

Front 9

When glasses (or contact lenses) are used to correct farsightedness, where should the corrective lens form an image of an object located between the eye and the near point in order for the eye to form a clear image of that object?

Back 9

The lens should form the image at the near point.

Front 10

Joe first focuses his attention (and his eyes) on the tree. The focal length of the cornea-lens system in his eye must be __________ the distance between the front and back of his eye.

Back 10

less than

Front 11

Joe's eyes are focused on the tree, so the squirrel and the mountain appear out of focus. This is because the image of the squirrel is formed ______ and the image of the mountain is formed _____.

Back 11

behind the fovea / between the lens and fovea

Front 12

Joe now shifts his focus from the tree to the squirrel. To do this, the ciliary muscles in his eyes must have _____ the curvature of the lens, resulting in a(n) _______ focal length for the cornea-lens system. Note that curvature is different from radius of curvature.

Back 12

increased / decreased

Front 13

Finally, Joe turns his attention to the mountain in the distance but finds that he cannot bring the mountain into focus. This is because he is nearsighted. But when Joe puts on his glasses, he can see the mountain clearly. To adjust for his nearsightedness, his glasses must contain _____ lenses.

Back 13

diverging

Front 14

To view an enlarged upright image of an object through a simple magnifier, where must the object be located?

Back 14

within the focal length of the lens, provided the focal length is shorter than the near point distance

Front 15

Two people, Micah and Lyra, with different near points are equally close to an object. Both inspect the object through the same magnifier by holding the lens close to the eye. Micah's near point is located farther away from his eye than Lyra's near point is located relative to her eye. Micah will experience a larger magnification for which of the following reasons?

Back 15

When the object is located at his near point, the angular size of the object is smaller for Micah than for Lyra.

The angular size of the image relative to the angular size of the object at the near point is greater for Micah than for Lyra.

Front 16

If a camera lens lets in an amount of light I when it is set to f/4, then how much light will it let in when it is set to f/8?

Back 16

I/4

Front 17

Which of the following are functions of the eyepiece lens of a refracting telescope?

Back 17

to produce an image whose angular size is greater than that of the object

to magnify the image produced by the objective lens

Front 18

What must result if the eyepiece lens of a refracting telescope is replaced with a lens that has a shorter focal length?

Back 18

The length of the telescope must be reduced.

The angular magnification produced by the telescope increases.

The angular size of the image seen by the viewer increases.

Front 19

Which are the components of a typical refracting telescope?

Back 19

a converging objective and a converging eyepiece

Front 20

Which of the following best decribes the object being viewed by the telescope?

Back 20

The object is essentially infinitely far away.

Front 21

The location of the object to be viewed far away results in what sort of image?

Back 21

an image at the focal point of the objective

Front 22

To form the virtual and enlarged images seen by the observer, the telescope should be designed so that the image formed by the objective falls where?

Back 22

slightly inside the focal length of the eyepiece

Front 23

How does the amplitude of the wave depend on the distance from the source?

Back 23

The amplitude decreases with distance.

Front 24

Which statement best describes how the intensity of the wave depends on position along the screen?

Back 24

The intensity is roughly constant.

Front 25

Which statement best describes how the intensity of the wave depends on position along the screen?

Back 25

The intensity is roughly constant.

Front 26

Which statement best describes how the intensity of light on the screen behaves?

Back 26

The intensity is large near the middle of the screen, then decreases to nearly zero, and then increases again as the distance from the middle of the screen increases.

Front 27

How does the distance between consecutive bright fringes depend on the wavelength of the light?

Back 27

The fringes get farther apart as wavelength increases.

Front 28

How does the distance between consecutive bright fringes depend on the slit separation?

Back 28

The fringes get closer together as the slit separation increases.

Front 29

How does the distance between the bright fringes depend on the slit width (for slit widths less than the wavelength of the light)?

Back 29

The spacing of the fringes does not change when the slit width changes.

Front 30

How does the distance between the bright fringes depend on the amplitude of the wave?

Back 30

The spacing of the fringes does not change when the amplitude changes (just the brightness changes).

Front 31

Does interference occur when water or sound waves encounter a barrier with two slits?

Back 31

Yes, interference also occurs for both of these types of waves.

Front 32

Which of the following statements are true concerning compound microscopes?

Back 32

In a compound microscope, the image formed by the objective lens is a real image.

In a compound microscope, the final image is a virtual image.