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One atomic mass unit (1 amu) is defined as:

1. 1/12 of C - 12
2. 1/14 of O - 16
3. 1g of H2
4. 1.66 × 10⁻²⁴ kg

Correct answer: 1/12 of C - 12

Solution

By definition, 1 amu = 1/12 of the mass of a carbon-12 atom (~1.66 x 10⁻²⁴ g); option D states kg which is incorrect by a factor of 1000.

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