What do you mean by mass defect? Actual mass of proton, neutron and helium nucleus are 1.00728 amu, 1.00867 amu and 4.0015 amu, respectively. What is the mass defect of ⁴₂He (helium) nucleus? [1+2]
Mass Defect : Mass defect is the difference between the sum of the masses of the individual nucleons (protons and neutrons) and the actual mass of the nucleus.
Given,
Mass of one proton = 1.00728 amu
Mass of one neutron = 1.00867 amu
Mass of helium nucleus = 4.0015 amu
A helium nucleus contains: 2 protons and 2 neutrons
Mass of 2 protons = 2 × 1.00728 = 2.01456 amu
Mass of 2 neutrons = 2 × 1.00867 = 2.01734 amu
Total mass of nucleons
= 2.01456 + 2.01734
= 4.03190 amu
Mass defect = Total mass of nucleons − Actual mass of nucleus
= 4.03190 − 4.00150
= 0.03040 amu
Hence, the mass defect of the helium nucleus is 0.0304 amu.
Related Questions
More WBBSE Moderate level questions