12) Fermium-253 has a half-life of 3.00 d. A sample of fermium contains 7.37 x 10 nuclei. How long will it take for there to be only 3.36 x 10 fermium nuclei in this sample? 13) Nuclear binding energy: The following masses are known: In (neutron) 1.008665 u 1H 1.007825 u 1 57 56.935399 u 26 What is the binding energy of Fe, in MeV? (1 u = 1.6605 x 10-27 kg =931.5 MeV/c2)