Question

Define mass defect of nucleus?

Answer 1

The mass defect of nucleus is the change in mass of nucleus with the sum mass of nucleon.
Mass of nucleus < total mass of proton and neutron. The mass of nucleus changes for to bonding between them by strong force. According to quantum relativity, the mass of proton and neutron came from quarks' potential, kinetic and thermal energy by gluon field, as for bond between proton and neutron by strong force, the potential energy gets change for bond in center of nucleas.

Answer 2

As, nucleaus is made up of proton and neutron . So, mass defect is that dfect in mass when the neutron and proton is free and when they combined in nucleaus. Means when proton and neutron is free there mass is high and when they combined in nucleus there mass is lowers down.