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Homework Help: Pressure of radiation

  1. Aug 5, 2011 #1
    1. The problem statement, all variables and given/known data

    Revered Members,
    While going through pressure of radiation topic in Thermal Physics, i got stumbled at this step.
    it has been given P = E/c
    If u is the energy density i.e energy per unit volume, then the total energy passing through area 's' of the surface normal to the incident radiation per second = ucs
    I dont know how this " ucs " has been arrived.
    Please help in this regard. Thanks in advance

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Aug 5, 2011 #2
    Perform a dimensional analysis as follows:

    u (energy / volume) = u (energy / length^3)

    u (energy / length^3)
    c (length / time)
    area(length^2) = energy / time

    Multiply this out and see if you can match the expected result.
  4. Aug 5, 2011 #3
    Beautiful sir. Thanks a lot, i got it now
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