(a) (b) Define the mass defect and the nuclear binding energy of a nuclide X in terms of its atomic mass. You are given the binding energy per nucleon (b = B/A) of three isobars: b(Ni) = 8.7649 MeV, b(Cu) = 8.7155 MeV and b(Zn) = 8.6102 MeV. Do you expect Cu to be - or B+ radioactive? Support your answer with quantitative arguments based on mass/energy balance. Useful masses: m = 938.2723 MeV/c, m = 939.5656 MeV/c and m = 0.511 MeV/c. Evaluate the Coulomb barrier Ec (in MeV) for the deuterium-tritium fusion reaction: d+t 2He+X What is the missing particle X? Estimate the minimal temperature 7 required to provide sufficient average kinetic energies k&T of the fusing nuclides to overcome the barrier Eg. Why is this reaction significant for fusion power? Hint: You can use the hard charged spheres approximation and the empirical formula for the nuclear radius as a function of the mass number with R = 1.2 fm. Other constants: 1/4 = 9.0 x 10 J-m/C, ka = 8.62 x 10- eV/K.