multiple questions for physics

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QUESTION 1

  1. During a solar eclipse, observers on Earth seeing a partial eclipse are standing in the

    a.

    umbra.
    b.

    penumbra.
    c.

    antumbra.
    d.

    image point.

2 points  

QUESTION 2

  1. Why can’t you see an image of an object if it is diffusely reflected instead of specularly reflected?

    a.

    The light rays are reflected in random directions, so rays don’t come together to form an image.
    b.

    The light rays are absorbed by the material and none reach our eyes.
    c.

    The frequency of the light rays changes upon reflection, making them invisible to us.
    d.

    Both A and C

2 points  

QUESTION 3

  1. Plane mirrors produce images that are

    a.

    virtual, upright, enlarged
    b.

    virtual, upright, true
    c.

    real, upright, true
    d.

    real, inverted, reduced

2 points  

QUESTION 4

  1. A red laser is fired at the surface of a glass block, striking the surface at a 35 degree angle relative to the normal. Knowing the index of refraction of the glass block n= 1.5, the light ray will bend:

    (Hint: Use Snell’s Law to find the new, refracted angle. Is it smaller or greater than 35 degrees?)

    a.

    toward the normal
    b.

    away from the normal
    c.

    the light ray will not bend at all
    d.

    impossible to tell from the information given

2 points  

QUESTION 5

  1. The glass block (n = 1.50) is placed on the surface of a container of water (n = 1.33). The beam of the red laser is adjusted so that it reaches the other side of the block at a 40 degree angle relative to the normal before refracting again as it goes from glass to water. At what angle relative to the normal does the light beam travel through the water?

    (Hint: Now, do Snell’s Law again but the ray goes from glass to water. Use the new value for the incident angle. What’s the refracted angle in this case?)

    40 degrees (the light ray doesn’t bend)

    46.5 degrees

    34.7 degrees

    58.4 degrees

2 points  

QUESTION 6

  1. A fish swims below the surface of the water, as shown in the accompanying figure. Suppose an observer is looking at the fish from the point O’ – straight above the fish. The observer sees the fish at

    viewing a fish under water

    a.

    A greater depth than it really is
    b.

    The actual depth it really is
    c.

    A shallower depth than it really is
    d.

    A position to the side of where it really is, but at the same depth

2 points  

QUESTION 7

  1. For angles of incidence exceeding a certain value, light traveling from a denser medium (higher index of refraction) to a less dense medium (lower index of refraction) is

    a.
    b.

    dispersed.
    c.

    bent at a sharp angle.
    d.

    totally reflected.

2 points  

QUESTION 8

  1. Red light of wavelength 750 nm in vacuum enters crown glass (n=1.55). The wavelength of light inside the glass is now

    a.
    b.

    1162 nm.
    c.

    240 nm.
    d.

    750 nm.

2 points  

QUESTION 9

  1. Looking straight down onto water (90 degrees to the surface), a light ray coming out of the water straight toward you is refracted

    a.
    b.

    toward the vertical.
    c.

    not at all (doesn’t change its path)
    d.

    at the critical angle.

2 points  

QUESTION 10

  1. A mirage is produced because

    a.
    b.

    light rays bend when they go from warm air to cool air and vice versa.
    c.

    images of water are reflected from the sky.
    d.

    light travels faster through air than through water.

2 points  

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