energy level

(a) Compton scattering occurs.
The hydrogen atom is excited to the first excited state. The scattered photon has an energy of (10.5 - 10.2) eV = 0.3 eV
(b) The hydrogen atom still remains at ground state, and the electron is scattered.


2011-12-17 09:29:29 補充：
Sorry...in (a) Compton scattering shall not occur at such low photon energy. The H atom still remains at ground state.