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: Power of a laser

  1. Apr 14, 2010 #1
    1. The maximum electric field strength in air is 3.0 MV/m. Stronger electric fields ionize the air and create a spark. What is the maximum power that can be delivered by a 1.3 cm diameter laser beam propagating through air?

    2. I = P/A = c*epsilon0*E2/2

    3. Using E = 3*106 for E, I use the above equation to solve for I, obtaining 1.19*1010. Multiplying by area, using pi*r2 and r = 0.013m, I obtain 6.34*106, which is incorrect.
  2. jcsd
  3. Apr 14, 2010 #2


    User Avatar
    Science Advisor
    Gold Member

    the diameter is 1.3cm so the radius is only .0065m
  4. Apr 14, 2010 #3
    ****.... thanks :(
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook