1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook