In a nuclear reactor, in the fission process, neutrons areemitted at high energies. Neutrons are to be thermalized, i.e.,their kinetic energies have to be significantly reduced, so thatyou can increase the probability for the new fission processes. Youhave a choice of a number of materials such as, say, heavy, water,iron and lead. The neutrons experience elastic collisions with theatoms of these materials and lose their energies. Assuming thetarget atoms are at rest initially, out of the three materialsgiven about which one would you prefer for the efficientthermalization of neutrons? Give reasons and explanation
