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Homework Help: Light and Optics

  1. May 15, 2006 #1
    *Answers may include more than one choice

    X-ray, visible light and infared radiation are differnt from each other because:

    --of differing frequencies-i know this is right
    --of differing energies--i am not sure as to whether this is right or wrong because from what i understand, different frequencies could lead to different enrgies (blue has more energy than red, etc)
    --of differing amplitudes--i know this is wrong
    --of differing velociites--i know this is wrong
    --they are not all electromagnetic waves---i know this is wrong

    A stained glass window
    --refracts light
    --reflects light
    --transmits light
    --absorbs light

    i am pretty sure about all of them being right except for transmitting light and refracting it. i think it could refract it because it turns it. i have no idea about transmitting light

    light goes from air to water; angle of incidence = 30

    i think light bends toward the normal because water has a greater index of refraction which slows light

    light goes from glass to air; angle of incidence=30

    pretty much the opposite of the previous one because it goes from a smaller index of recraction to a greater one

    light slows down; angle of incidence=30

    i dont think there is enough information to conclude whether this goes away or towards the normal

    used to magnify objects--i believe that this is a characteristic of concave mirrors and converging mirrors, but i'm not sure if it is characteristic of diverging mirrors--i belive that this NEVER makes an image larger

    an object inside a focal point of a convering lens forms an image that is

    b.upside down
    c real
    d virtual
    e larger than the object
    f smaller than the object
    g the same size as the object

    i'm sure it creates an upright and virtual image...but whether it is smaller or larger than the object i'm not sure, because it could be both depending on where it is looked from

    the photoelectric effect

    a can be used to create electric current
    b occurs when light shining on a n emitting surface has a minimum intensity
    c occurs when light shinng on an emitting surface has a minimum frequency
    d supports the wave theory of light
    e supports the particle nature of light

    i'm pretty sure that a and b are correct, but i am not sure if e is correct

    thank you in advance
    Last edited: May 15, 2006
  2. jcsd
  3. May 15, 2006 #2

    Andrew Mason

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    In 1. the photons have different energies and frequencies. Energy is proporational to frequency.

    In the last one, b is not right and you are missing one of d and e.

  4. May 15, 2006 #3


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    Note that the speed of light in a medium is equal to c/n. So if light slows down as it goes from a medium A to a medium B, it means that the index of refraction of B is larger than the index of A. That should tell you how to answer the question

    Draw a ray diagram and you will see right away.
  5. May 16, 2006 #4
    hi, thanks for the responses, i have 2 more that i am unsure about

    a mirage is caused by:
    reflection--this is the choice i am unsure about b/c i think it does reflect and refract at the same time but it didnt mention aanything about reflection in my text

    the difference in the path length of the interfering rays at the first order dark is

    1/2 wavelength

    i'm sure the whole numbers are wrong, and i'm sure that 1/2 is right, but i dont know about the other 3/2 and 5/2 because 1/2 is a condition only under the first dark fringe, but w/ the other ones, 2nd..3rd...it increases by an odd number of half wavelength. correct?
  6. May 16, 2006 #5


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    Spot on :smile:

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