Topic Moderator
Asked 2 times across 2 UPSC exams over 9 years (2014–2023), peaking in 2014.
Key insights
- Most tested in CDS — 1 of 2 PYQs
- Most asked in 2014
- Recurs across 2 years (2014–2023)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CDS 2014 → GEO 2023
How the concept evolved
Long-running — most appearances (1 of 2) predate 2016, and it still returns.
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.
GEO2023
What is the use of heavy water?
- A It is used in nuclear reactors as a moderator ✓
- B It is used in nuclear reactors as fuel
- C It is used in radiation therapy for cancer
- D It is used in water softening plants
✓ Correct answer: (A)
Science & Technology › Energy & Nuclear
CDS2014
Carbon or Graphite rods are used in atomic reactors as moderators for sustained nuclear chain reaction through nuclear fission process. In this process
- A the neutrons are made fast
- B the protons are made fast
- C the neutrons are made slow ✓
- D the protons are made slow
✓ Correct answer: (C)
Science & Technology › Energy & Nuclear
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