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Topic Mass-energy equivalence
Asked 2 times across 2 UPSC exams over 4 years (2021–2025), peaking in 2021.
Key insights
- Most tested in NDA — 1 of 2 PYQs
- Most asked in 2021
- Recurs across 2 years (2021–2025)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
NDA 2021 → GEO 2025
How the concept evolved
Rising — more than half its appearances (2 of 2) are since 2016.
Related concepts
Ideas UPSC tests alongside this one — keep exploring.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
GEO2025
The masses of ⁴₂He, ³₁H and ¹₁H nuclides are respectively 4·002603 amu, 3·016056 amu and 1·007276 amu. How much energy should a γ-ray photon possess if it is to split an α-particle into a tritium (³₁H) and a proton (¹₁H)? (Given that 1 amu of mass is equivalent to 931 MeV)
- A 19·30 MeV ✓
- B 0·931 MeV
- C 0·021 MeV
- D 0·194 MeV
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
NDA2021
Nuclear energy is generated by
- A nuclear fission and its expression was proposed by Einstein. ✓
- B nuclear fission and its expression was proposed by Rutherford.
- C nuclear fission and its expression was proposed by Bohr.
- D nuclear fission and its expression was proposed by Heisenberg.
✓ Correct answer: (A)
Science & Technology › Energy & Nuclear
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