- #1
G Cooke
- 33
- 3
I'm having trouble seeing how electric potential energy production on a conductor follows conservation of energy.
Let's use the photoelectric effect as an example. A photon with energy E = hν strikes a conductor, ejecting a photoelectron with a maximum kinetic energy of hν - φ. Assuming the maximum kinetic energy is achieved, this leaves only φ to be transferred from the photon into the conductor.
However, we know that electrical energy follows the equation E = QV = Q2/C, which implies that the electric potential energy produced on the conductor by the photoelectric effect is equal to Eprod = Efin - Einit = (Qinit + Qelec)2/C - Q2init/C, which clearly increases with initial charge. Since φ is a constant, this implies that it is possible for Eprod to be greater than φ, which appears to violate conservation of energy since φ was the total amount of energy that entered the conductor.
Clearly I'm missing something. Any help would be much appreciated.
Let's use the photoelectric effect as an example. A photon with energy E = hν strikes a conductor, ejecting a photoelectron with a maximum kinetic energy of hν - φ. Assuming the maximum kinetic energy is achieved, this leaves only φ to be transferred from the photon into the conductor.
However, we know that electrical energy follows the equation E = QV = Q2/C, which implies that the electric potential energy produced on the conductor by the photoelectric effect is equal to Eprod = Efin - Einit = (Qinit + Qelec)2/C - Q2init/C, which clearly increases with initial charge. Since φ is a constant, this implies that it is possible for Eprod to be greater than φ, which appears to violate conservation of energy since φ was the total amount of energy that entered the conductor.
Clearly I'm missing something. Any help would be much appreciated.