In particular, if a 2.000Å (.2nm) photon interacts with the bound electron in an
ID: 1940238 • Letter: I
Question
In particular, if a 2.000Å (.2nm) photon interacts with the bound electron in an hydrogen atom(binding energy 13.6 eV) with a Compton collision. The electron moves forward in the same direction as the incident photon. It may be convenient to use hc ? ? 12408eV Å
a) What is the kinetic energy of the electron?
b) What is the energy of the scattered photon?
c) Why is the total energy of the scattered photon and scattered electron equal to the incident photon energy? (I.e. at what point(s) was the 13.6 eV binding energy
ignored?)
Explanation / Answer
Energy of the incident photon : 6.2KeV ;
the binding energy is much smaller than the energy of incident photon and hence can be neglected.
given the electron moves in the same direction as that of incident photon.
=> the incident photon bounces back 180 deg . this comes from momentum conservation.
and from the formula for shift in wavelength of photon we have :
and = 180 deg.
=>
l2 - l1 = h/moc (1- Cosq)