# Homework Help: Compton Scattering given Energy of Scattered Gamma.

1. Jul 16, 2011

### atomicpedals

1. The problem statement, all variables and given/known data

Gamma rays of energy 1.02MeV are scattered from electrons which are initially at rest. Find the angle for symmetric scattering at this energy. What is the energy of the scattered photon from this case?

2. Relevant equations

$\Delta$ $\lambda$ = 0.0243A (1 - cos $\theta$ )

3. The attempt at a solution

What's throwing me off on this problem is the use of the gamma energy (1.02MeV). I'm perfectly equipped to handle this problem given wavelengths. Do I need to go back and calculate out the wavelength from conservation of energy? Any hints in the right direction are much appreciated.

Thanks.

2. Jul 17, 2011

### Mike Pemulis

The energy of a photon is given by E = hc/lambda, where h is Planck's Constant and c is the speed of light. You can use this to convert between energy and wavelength.

3. Jul 17, 2011

### atomicpedals

Can't believe I missed that, thanks!