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: Intensity with mirrors

  1. Mar 19, 2007 #1
    1. The problem statement, all variables and given/known data

    The EPM has finally crossed the fine line between party tricks and felonies
    with the genocide of the pigmy marmoset. You are now determined to make him '
    pay the price. You fashion a makeshift sherical mirror/laster beam our of a
    roll of aluminum foil and a stick of bubblegum. Considering the power radiated
    from the sun lands on earth with a maximum flux of almost a kilowatt per square

    How large should the surface of the mirror be, if you are to deliver over a
    megawatt per square meter over a 1 square centimeter monkey-butt surface?

    2. Relevant equations

    I = P / A
    3. The attempt at a solution

    I have tried this several times but I don't see the link between everything. I obviously have to use I = P / A and solve for A(mirror)
  2. jcsd
  3. Mar 20, 2007 #2
    Just to clarify, this is a mirror and not a lens...right?
  4. Mar 20, 2007 #3
  5. Mar 20, 2007 #4
    The question as i am reading isnt very clear. You would have to have a parabolic mirror to focus the light...so it would depend...unless im missing something
  6. Mar 20, 2007 #5
    it's a spherical mirror...specifically a concave sphere.......

    I know i have to use intensity but i don't know how i can relate the suns intensity to that of the mirror ; and / or power
  7. Mar 20, 2007 #6
    Well, it would depend on the focal length of the mirror and the distance between obects
  8. Mar 20, 2007 #7
    does the problem want a numerical answer, or an equation as a function of focal length and distance?
  9. Mar 20, 2007 #8
    You have as much information as I do. It is all stated above. It wants to know how much area the mirror must have. hence i find the Intensity possibly very useful, since I = P / A .... but how can P be related from the sun to the mirror
  10. Mar 20, 2007 #9
    Well, a mirror of size A=1000m^2 would obviously give you that amount of energy...but im not sure about other parameters and how they would affect...sorry
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook