Question

The mass of a neutral carbon atom in ground state is

Options

• exact 12 u

• less than 12 u

• more than 12 u

• depends on the form of carbon such as graphite of charcoal.

Answer 1

exact 12 u

In nuclear physics, a unit used for measurement of mass is unified atomic mass unit, which is denoted by u.

It is defined such that

1 u =  `1/12 xx` (Mass of neutral carbon atom in its ground state)

Mass of neutral carbon atom in its ground state = 12 × 1 u = 12 u

Thus, the mass of neutral carbon atom in its ground state is exactly 12 u.