Question
Obtain the binding energy of the nuclei and in units of MeV from the following data:
Solution
i)
contains 26 protons and,
Number of neutrons = (56 - 26) = 30 neutrons
Now,
Mass of 26 protons = 26 x 1.007825 = 26.20345 u
Mass of 30 neutrons = 30 x 1.008665 = 30.25995 u
Total mass of 56 nucleons = 56.46340 u
contains 26 protons and,
Number of neutrons = (56 - 26) = 30 neutrons
Now,
Mass of 26 protons = 26 x 1.007825 = 26.20345 u
Mass of 30 neutrons = 30 x 1.008665 = 30.25995 u
Total mass of 56 nucleons = 56.46340 u
Mass of nucleus = 55.934939 u
Mass defect,
Total binding energy = 0.528461 x 931.5 MeV = 492.26 MeV
Average binding energy per nucleon =
ii)
nucleus contains 83 protons and,
Number of neutrons = (209-83) = 126 neutrons.
Mass of 83 protons = 83 1.007825 = 83.649475 amu
Mass of 126 neutrons = 126 1.008665 = 127.091790 amu
Therefore, total mass of nucleons = (83.649475+127.091790) = 210.741260 amu
mass of nucleus = 208.980388 a.m.u (given)
Now, mass defect, = 210.741260 - 208.980388 = 1.760872
Total binding energy = 1.760872 931.5 = 1640.26 MeV
Therefore, average B.E. per nucleon = = 7.848 MeV
Mass defect,
Total binding energy = 0.528461 x 931.5 MeV = 492.26 MeV
Average binding energy per nucleon =
ii)
nucleus contains 83 protons and,
Number of neutrons = (209-83) = 126 neutrons.
Mass of 83 protons = 83 1.007825 = 83.649475 amu
Mass of 126 neutrons = 126 1.008665 = 127.091790 amu
Therefore, total mass of nucleons = (83.649475+127.091790) = 210.741260 amu
mass of nucleus = 208.980388 a.m.u (given)
Now, mass defect, = 210.741260 - 208.980388 = 1.760872
Total binding energy = 1.760872 931.5 = 1640.26 MeV
Therefore, average B.E. per nucleon = = 7.848 MeV