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One atomic mass unit (1 amu) is defined as which of the following?
AMass of one carbon-12 atom
BOne-twelfth of the mass of a carbon-12 atom
CMass of one hydrogen atom
DOne-sixteenth of the mass of an oxygen atom
Answer & Solution
Correct answer: B. One-twelfth of the mass of a carbon-12 atom
1. The atomic mass unit is a relative scale based on carbon-12.
2. A carbon-12 atom is assigned a mass of exactly 12 amu.
3. Therefore 1 amu equals one-twelfth of the mass of a carbon-12 atom.
_Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 7 Atoms and Molecules "Atom and Atomic Mass", p.99_
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