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Topic Longitudinal waves
Asked 3 times across 2 UPSC exams over 4 years (2021–2025), peaking in 2021.
Key insights
- Most tested in NDA — 2 of 3 PYQs
- Most asked in 2021
- Recurs across 3 years (2021–2025)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
NDA 2021 → GEO 2025
How the concept evolved
Rising — more than half its appearances (3 of 3) 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.
GEO2025
A sound wave consists of
- A a compression pulse and a rarefaction pulse separated by a distance of one wavelength
- B compression and rarefaction pulses one after the other ✓
- C a number of rarefaction pulses one after the other
- D a number of compression pulses one after the other
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
NDA2023
Which one of the following statements is true for sound waves propagating in air ?
- A Sound is an electromagnetic wave and transverse in nature
- B Sound is a mechanical wave and longitudinal in nature ✓
- C Sound is a mechanical wave and transverse in nature
- D Sound is an electromagnetic wave and longitudinal in nature
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
NDA2021
Which among the following is true for propagation of sound waves ?
- A Sound can travel in vacuum and it is a transverse wave in air.
- B Sound cannot travel in vacuum and it is a longitudinal wave in air. ✓
- C Sound can travel in vacuum and it is a longitudinal wave in air.
- D Sound cannot travel in vacuum and it is a transverse wave in air.
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
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