Topic Sound
Asked 9 times across 4 UPSC exams over 31 years (1994–2025), peaking in 2023.
Key insights
- Most tested in CDS — 4 of 9 PYQs
- Most asked in 2023
- Recurs across 6 years (1994–2025)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CSE 1994 → CDS 2019 → NDA 2021 → CAPF 2024
How the concept evolved
Rising — more than half its appearances (8 of 9) 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.
NDA2025
We hear an echo due to
- A Refraction of sound waves
- B Reflection of sound waves ✓
- C Diffraction of sound waves
- D Resonance due to sound waves
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
CAPF2024
Which one of the following is the audible range of hearing for humans?
- A 20 kHz – 200 kHz
- B 20 Hz – 20 kHz ✓
- C 20 Hz – 35 kHz
- D 20 Hz – 40 kHz
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
CDS2023
Sonic boom is produced when a source of sound travels at a speed :
- A greater than the speed of sound. ✓
- B greater than the speed of light.
- C lesser than the speed of sound.
- D equal to the speed of sound.
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
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