A sphere of radius r1 collides with a sphere of radius r2.The cross section for a contact collision is
D)½(r1 + r2)2
E)(r1 + r2)2
A thermal neutron is a neutron whose kinetic energy is in thermal equilibrium with its surroundings.At room temperature this energy is approximately
Neutrons are effective particles for penetrating the nucleus because of their
C)lack of charge.
A thermal neutron
A)produces electrons by thermionic emission.
B)produces protons by thermionic emission.
C)ionizes atoms by an increase in thermal energy.
D)creates an electron-positron pair by an increase in thermal energy.
E)gains kinetic energy as often as it loses it at room temperature.