Write an equation for the average fractional energy loss ΔE of a neutron in an elastic collision with a Carbon-12 atom having an atomic weight of 12. Suppose that an experiment reveals that the...

Write an equation for the average fractional energy loss ΔE of a neutron in an elastic collision with a Carbon-12 atom having an atomic weight of 12.

Suppose that an experiment reveals that the average scattering angle of a neutron is 75°. What is the atomic weight of the material with which the neutron is scattering?