The electron is now allowed to decay to its ground state. Which of the following is a correct statement about the photon emitted during this decay process?
1) The photon emitted has a frequency equal to the difference in energy between the electron's initial and final states
2) The photon emitted has a frequency equal to the energy of the electron's ground state
3) The photon emitted has a frequency equal to the energy of the electron's excited state
4) The photon emitted has a frequency equal to the energy of the electron's initial state