MASS DEFECT AND BINDING ENERGYDOE-HDBK-1019/1-93Atomic and Nuclear PhysicsExample:Calculate the mass defect for lithium-7. The mass of lithium-7 is 7.016003 amu.Solution:D m Zmp meA Z mnmatomD m 31.007826 amu 7 3 1.008665 amu 7.016003 amuD m 0.0421335 amuBindingEnergyThe loss in mass, or mass defect, is due to the conversion of mass to binding energy when thenucleus is formed. Binding energy is defined as the amount of energy that must be supplied toa nucleus to completely separate its nuclear particles (nucleons). It can also be understood asthe amount of energy that would be released if the nucleus was formed from the separateparticles. Binding energy is the energy equivalent of the mass defect. Since the mass defectwas converted to binding energy (BE) when the nucleus was formed, it is possible to calculatethe binding energy using a conversion factor derived by the mass-energy relationship fromEinstein's Theory of Relativity. Einstein's famous equation relating mass and energy is E = mc2 where c is the velocity of light(c = 2.998 x 108 m/sec). The energy equivalent of 1 amu can be determined by inserting thisquantity of mass into Einstein's equation and applying conversion factors.E m c21 amu1.6606 x 1027kg1 amu2.998 x 108msec21 N1kgmsec21 J1 Nm1.4924 x 1010J1 MeV1.6022 x 1013J931.5 MeVConversion Factors:1 amu = 1.6606 x 10 -27 kg1 newton= 1 kg-m/sec21 joule= 1 newton-meter1 MeV= 1.6022 x 10-13 joulesNP-01Page 18Rev. 0
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