11/ Free neutrons in nuclear reactors have many different collisions. Which collision below could be an elastic collision?

Select one:

Heavy water slows down free neutrons as a result of collisions.

Metal in the reactor may crack from collisions with free neutrons.

Cadmium control rods absorb the free neutrons that collide with them.

A uranium 235 atom is split by a collision with a free neutron.

13/ The CERN Large Hadron Collider accelerates protons to 99.999% of the speed of light giving the protons a momentum of A x 10^-B kgm/s. The value of A to three significant digits is Answer.