Solved UPSC CDS/OTA Question
A solved UPSC CDS/OTA PYQ — decoded step-by-step.
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Q · Atoms and MoleculesMedium · 45s
What is the mass of 1 atom of carbon-12?
TopicAtoms and Molecules
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained — no skipped algebra.
1 mole C-12 = 12 g, so one atom = 12/6.022×10²³ ≈ 1.99×10⁻²³ g.
Final Answer: Option D — 1.99 x 10⁻²³ g