The mass of a H-atom is less than the sum of the masses of a proton and electron. Why is this?

Explanation

By Einsteins. equation relation between energy and mass,
`E = mC^(2)`
E = energy, m = mass decayed (disintegrated)
C = speed of light
Here mass defect
`Deltam = (m_(p) + m_(e)) - M`
M= mass of H atom
But binding energy
`B*E=DeltamC^(2)`
`:.(B*E)/(=DeltamC^(2)`
`:.(B*E)/(C^(2))=Deltam=m_(p)+m_(e)-M`
`:.M lt m_(p)+m_(e)`
Thus, mass of H atom is less than total mass of electron and proton in free state.