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UPSC Combined Geo-Scientist

Chemist

  • 3 descriptive papers
  • 200 marks each
  • 3 h per paper

Mains Paper I covers inorganic chemistry.

UPSC Combined Geo-Scientist, Mains · 2025 · Mains Paper I

Q9(a). Binding energy per nucleon; fusion and fission

Question

Draw the average binding energy per nucleon (in MeV) against atomic mass number plot. Mention the salient features of this plot. On the basis of this plot, how will you explain the chances of nuclear fusion and fission processes?

Answer in brief

B/A rises steeply for light nuclei, peaks at about 8.8 MeV near A = 56–62 (Fe, Ni) and falls slowly to about 7.6 MeV for uranium; moving towards the maximum releases energy, by fusion of light or fission of heavy nuclei.

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Topic notes: nuclear chemistry: radioactive decay, binding energy, radiocarbon dating and the GM counter, with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversbinding energy per nucleonbinding energy curvenuclear fissionnuclear fusioniron-56mass defect

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