10. A beam of -particles, of kinetic energy 5.30 MeV and intensity 10* particle/sec, is in- cident normally on a gold foil of density 19.3 g/cm, atomic weight 197, and thickness 1.0 x 10-5 cm. An a particle counter of area 1.0 cm2 is placed at a distance 10 cm from the foil. If O is the angle between the incident beam and a line from the center of the foil to the center of the counter, use the Rutherford scattering differential cross section, (4-9), to find the number of counts per hour for = 10 and for O = 45. The atomic number of gold is 79. %3D