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Topic Doppler effect
Asked 2 times across 2 UPSC exams over 30 years (1990–2020), peaking in 1990.
Key insights
- Most tested in CSE — 1 of 2 PYQs
- Most asked in 1990
- Recurs across 2 years (1990–2020)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CSE 1990 → CAPF 2020
How the concept evolved
Long-running — most appearances (1 of 2) predate 2016, and it still returns.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
CAPF2020
The radar used by police to check over-speeding vehicles works on the principle of
- A Raman effect
- B Induction effect
- C Doppler effect ✓
- D Coulomb effect
✓ Correct answer: (C)
Science & Technology › Physics & Chemistry
CSE1990
The evidence for the rotation of stars comes mainly from the
- A Doppler effect
- B Photoelectric effect
- C Stark effect
- D Zeeman effect ✓
✓ Correct answer: (D)
Science & Technology › Space Tech
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