# Compton Scattering Help

1. Sep 7, 2009

### KingNothing

1. The problem statement, all variables and given/known data
48. If a 6.0 keV photon scatters from a free proton at rest, what is the change in the photon's wavelength if the photon recoils at 90 degrees?

52. A gamma ray of 700 keV energy compton-scatters from an electron. Find the energy of the photon scattered at 110 degrees, the energy of the scattered electron, and the recoil angle of the electron.

2. Relevant equations
$$\Delta\lambda=\frac{h}{mc}(1-cos(\theta))$$

3. The attempt at a solution
48. Since the angle is 90 degrees, the change in wavelength should be one compton wavelength. I don't see where the energy of the photon comes into play.

52. Again, I don't see where the energy comes into play.

2. Sep 8, 2009

### kuruman

48. You are correct here. For the change in wavelength you don't need the energy of the photon.

52. To find the new energy you need the new wavelength which you cannot find merely from the change in wavelength. You need to add the change in wavelength to the initial wavelength which you get from the initial energy.