What is the mass defect? and binding energy in MeV for atom?

The atomic mass of Helium-3 (3/2He) is 3.014694 amu. Calculate the:
a) mass defect for this atom?
b) binding energy in MeV for this atom?

1 Answer
Nov 17, 2017

Actually the sum of mass of individual ( say ( 2 proton and 2 neutron) nucleons is slightly greater than mass of atom made of those nucleons ( 2He4)
is different. Some amount of mass is used to bind those nucleons.
The difference in mass is known as mass defect.

Explanation:

Mass of Proton is 1.0072764 amu
Mass of Neutron 1.0086649 amu
So, mass of (2 proton and 1 neutron) is 3.023216 amu
and mass of He(3,2) is given 3.014694 amu
Mass difference #deltam=0.008522 # amu
Using 1 amu =931 mev
binding energy is #(0.008522*931)=7.933 Mev#