posted by qwer .
Hydrogen atom is initially in the ground state. It is excited by a photon bombardment and it then undergoes a transition from n = 3 to n=2 state.
a) What is the frequency of the bombarding photon?
b) What are the energy, momentum and the wavelength of the emitted photon?
c) Assume that atom is initially at rest, with what kinetic energy does it recoil when it emits a photon described in part (b)?
d) How many revolutions does an electron make in n=3 state before dropping to state n = 2. Assume that the lifetime of an electron in n=3 state is 10ns. (Hint; the speed of the electron in the nth orbit is given by