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Homework Help: Magnetic field intensity questions

  1. Aug 26, 2005 #1
    I tried reading my textbookfor the answers to these questions, but I can't find an answer. Can someone answer these questions?

    1. Changing the magnetic field intensity in a closed loop of wires induces
    A. Current
    B Voltage
    C. Both
    D. Neither

    2. True or False: Energy emitted by vibrating electrons is carried by electromagnetic waves.

    3. True or False: Glass is transparent to visible, infrared, and ultraviolet light.

    4. True or False: Two colors that add together to form black light are complementary colors.

    5. The color that travels fastest through clear glass is:
    A red
    B. green
    C. violet
    D. all travel at the same speed in clear glass

    6. A tennis ball is more easily seen if its color is
    A. white
    B. black
    C. violet
    D. yellow-green (I think it's this one)

    7. When the color yellow is seen on your TV screen, the colors being activated on the screen are
    A. mainly yellow
    B. blue and red
    C. green and yellow
    D. red and green

    8 The cyan color of ocean water is evidence that the water absorbs
    A. red
    B. orange
    C. yellow
    D. green
    E. blue

    9. The three colors that make up the colored photographs in books are
    A. red, green, and blue
    B. red, green, and yellow,
    C. magenta, yellow, and blue
    D. magenta, cyan, and yellow

    10. The white caps of waves as they overturn is evidence that the water has
    A. absorbed black
    B. broken into an assortment of tiny particles that scatter all colors
    C. lost its transparency
    D. reflected red, green, and blue light

    11. If the atmosphere of a planet scatters low frequency light more than high frequency light, sunsets on the planet appear
    A. reddish
    B. bluish
    C. whitish
    D. blackish

    12. True or False: A lens can amplify the amount of light energy incident upon it.

    13. The shiny surfaces of metals has most to do with:
    A. the looseness of electrons in metal atoms
    B. the metals' relatively high density
    C. the fact that light reflects from metals
    D. a resonant frequency of electrons in the metal

    14. It is difficult to see the roadway from the car on a rainy night because the road surface:
    A. absorbs the light more when wet
    B. becomes more mirrored and less diffuse when wet
    C. is obscured by the rain itself
    D. scatters light in all directions

    15. When we see the sun touching the horizion at sunset, it is actually below the horizon due to
    A. polarization
    B. reflection
    C. refraction
    D. interference
    E. diffraction

    16. The explanation for a filled root beer mug looking fuller than it is involves:
    A. reflection
    B. refraction
    C. both
    D. neither

    17. In a double rainbow, the outermost color in the outermost bow is
    A. red
    B. green
    C. blue
    D. any of these at different times

    18. All lenses rely on the fact that light has a
    A. consistent speed everywhere
    B. slower speed in the lens
    C. wavelength and frequency, the product of which equals c
    D. none of these
    Last edited: Aug 27, 2005
  2. jcsd
  3. Aug 26, 2005 #2


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    Science Advisor
    Homework Helper
    Gold Member

  4. Aug 27, 2005 #3
    Ok, these are my answers:
    1. C
    2. True
    3. True
    4. False
    5. D
    6. D
    7. A
    8. A
    9. A
    10. B
    11. A
    12. True
    13. C
    14. B
    15. C
    16. B
    17. D
    18. D

    If they're wrong, can you confirm why?
  5. Aug 28, 2005 #4


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    Homework Helper

    Since you]re guessing I'll just address a few points:
    3) regular glass absorbs strongly in the UV - we have to use quartz.
    5) A - haven't you seen glass prisms make "rainbows"?
    (violet light is *slow* in glass *because* glass absorbs UV!)
    6) I would go with A for this, since they don't say what color light it is in!
    7) TV screens - like computer monitors - don't emit yellow light, they're RGB!
    8) Which 2 colors of RGB light would need to be reflected to make "cyan" light?
    11) Re-read the IF part - does the red or the blue get removed first?
    18) ever hear of index-of-refraction? The marching-band entering a plowed field?
    17) Yea, Nature does whatever it D*M* well wants, there's just no pattern to it -
    no wonder nobody can understand it, so nobody can manipulate or control it -
    that's why we're still stuck in the stone age for the last 3 million years ... .
    Looks like you got NOTHING out of this class - is that less than you put into it?
  6. Aug 28, 2005 #5
    Thanks for the hints, don't quite understand #17 though...
    Actually, I didn't even start the class yet, this is the summer assignment :P
  7. Aug 28, 2005 #6


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    Staff: Mentor

    Ai-yi-yi! :eek: Eighteen questions in a single thread is a surefire recipe for mass confusion if people actually started discussing all of them at once.

    My suggestion is to post one problem per thread, and don't have too many threads active at once so it doesn't look like you're hogging the board. :smile: Give the thread a title that says something about what the problem is about, so people who feel like experts in that area will be attracted to it. If you have any ideas on what the answer might be, tell us, and explain your thinking. Then people can figure out any conceptual problems you might be having. If you don't have any idea, just ask for hints that might steer you in the right direction. It doesn't do any good for you in the long run, for us to just give you the answers.
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