ANSWER:
Atomic Mass Unit (amu):
“The unit used to express the relative atomic mass is called atomic mass unit (amu). It is 1/12th of the mass of one carbon atom.”
On C–12 scale, the relative atomic mass of 6C12 is 12.0000 amu and that of 1H1 is 1.008 amu.
1 a.m.u. = 1.661×10–27 kg
(Ref. An Insight Into Objective Chemsitry-11, Ch-01, Q. No. 15)