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Homework Help: Some math questions I need checked

  1. Apr 24, 2005 #1
    10. the picture that we see in a mirror is called the
    my answer=image
    11. the actual object that makes a picture that we see on a mirror is called the
    my answer=specular

    -problems- show your work

    15. What is the wavelength of a wave with a frequency of 100.4 MHz?

    16. A substance allows light to travel through it with a velocity of 2.45 x10^8 m/s. What is the substances index of refraction?

    17. What is the intensity of a light that has a lumnious flux of 750 lumens?

    18. What is the illuminance provided by a light with a luminous flux of 1120 lm when it is 2.3 meters away?

    19. What would the angle of refraction be if a light ray starts in a diamond and goes into the air it has an angle of incidence of 9 degrees.

    20. What is the critical angle of light going from quartz to air?

    22. What is the illuminance of a light when it is 4.6 m away from a light with an intensity of 78 candle power?

    thanks for any help I dunno what im doing

    Here's my answers:

    #15: .335 m
    #16: 1.22
    #17: I was not sure how to do this one.
    #18: I was also not sure how to do this one.
    #19: 24.44 degrees
    #20: 40.37 degrees
    #22. 3.6
  2. jcsd
  3. Apr 24, 2005 #2
    Show that you've tried. Providing the answers is not enough.
  4. Apr 24, 2005 #3
    #15: 100.4 x 10^6

    3 x 10^8

    divide c by f


    #16: 2.45 x 10^8/ 3x 10^8 =1.22
    #17: Like I said, I dunno what to do
    #18: Dunno what to do
    #19: 2.417(SIN)Q2=1(SIN)90
    =24.44 degrees
    #20: I just plugged it in and got 40.37 degrees for this one
    SIN X= 1/1.544 then I did some other work to get the angle

    #22: I wasn't really sure with this one but I used the illuminance equation to solve. I doubt it's right.
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