1. The problem statement, all variables and given/known data Calculate the cross section for the scattering of a 10 MeV alpha particle by a gold nucleus (Z=79, A=197) through an angle greater than a) 10 degrees b) 20 degrees c) 30 degrees. Neglect Nuclear recoil. 2. Relevant equations http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/crosec.html 3. The attempt at a solution I've seen a number of equations that relate to rutherford scattering. The one on hyperphysics looks neat, but it doesn't say what the variables in the equation are. I don't know what the small 'ke' means and what the two angles are supposed to be in the equation either. I'm assuming they are both the scattering angle.