Home / Topic / Atmospheric refraction
Topic Atmospheric refraction
Asked 5 times across 4 UPSC exams over 9 years (2013–2022), peaking in 2022.
Key insights
- Most tested in NDA — 2 of 5 PYQs
- Most asked in 2022
- Recurs across 3 years (2013–2022)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CSE 2013 → NDA 2021 → CDS 2022 → CISF 2022
How the concept evolved
Rising — more than half its appearances (4 of 5) 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.
CDS2022
The twinkling of a star is due to :
- A atmospheric reflection of starlight.
- B atmospheric refraction of starlight. ✓
- C continuous change in the position of the star.
- D oscillation of starlight.
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
CISF2022
What is the time difference between the actual sunset and apparent sunset ?
- A About half a minute
- B About one minute
- C About two minutes ✓
- D About twenty minutes
✓ Correct answer: (C)
Geography › Climatology
NDA2021
Twinkling of stars is primarily due to the atmospheric
- A refraction ✓
- B reflection
- C polarization
- D dispersion
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
Study how UPSC repeats — not just the papers
₹199 / 1 year · Founding Member
Full access unlocks the three things no PYQ PDF gives you:
① Cross-exam learning — see the same idea recur across CSE, CAPF, CDS and NDA.
② Topic evolution — how each idea is framed, year by year.
③ Question intelligence — every PYQ + answer, linked to related concepts and similar questions.
e.g. Round Table Conference: CDS 2017 → CSE 2017 → … → CAPF 2024
15 days free, no card required — then ₹199 for 1 year.
Start your 15-day free trial →