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Homework Help: Number of photons to make a black hole

  1. Feb 1, 2009 #1

    By setting the total energy of photons to Mc^2, estimate the maximum number of photons that could be used to make a black hole of mass M.

    This is a thermal physics problem, in case anyone needs a context; we're discussing the entropy of a black hole.

    2. Relevant equations

    I'm given the entropy for a black hole. I also know the Schwarzschild radius.

    3. The attempt at a solution

    I'm just having trouble seeing where to start. Probably this is something very basic and I'm just missing it. Can someone just help me to start?
  2. jcsd

Can you offer guidance or do you also need help?
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