Bill, that’s a good concise explanation of what happens, but it still leaves Paul’s question unanswered. Granted, the energy to move the electron comes from the incident photon, but if the emitted photon has the same energy, then the electron has been moved without expenditure of energy. Orac may be right, Paul may be trolling, but every unanswered question is a gift of troll-space. (Is that a working term, or have I just invented one?)

There never was nothing.