Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Eduncle
Dear Dibya Ranjan,
Greetings!
Here is the solution of your query.
Carbon-12 is the standard while measuring the atomic masses. Because no other nuclides other than carbon-12 have exactly whole-number masses in this scale. This is due to two factors: the different mass of neutrons and protons acting to change the total mass in nuclides with proton/neutron ratios other than the 1:1 ratio of carbon-12; and an exact whole-number will not be located if there exists a loss/gain of mass to difference in mean binding energy relative to the mean binding energy for carbon-12.
Oxygen was used as a standard for quite some time, but the results seem to be different in certain experiments. This was because oxygen-17 and oxygen-18 are also present in natural oxygen this led to 2 different tables of atomic mass. The unified scale based on carbon-12, 12C, met the physicists' need to base the scale on a pure isotope while being numerically close to the chemists' scale.
Thank you for asking your query.