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Topic Vapour pressure
Asked 2 times across 2 UPSC exams over 2 years (2023–2025), peaking in 2023.
Key insights
- Most tested in NDA — 1 of 2 PYQs
- Most asked in 2023
- Recurs across 2 years (2023–2025)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
NDA 2023 → GEO 2025
How the concept evolved
Rising — more than half its appearances (2 of 2) 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
The saturation vapour pressure at 300 K is 3·6 kPa and the gas constant R is 8·3 J/(K·mol). The mass of water vapour per m³ of air at temperature 300 K and relative humidity 50% is
- A 13 g ✓
- B 26 g
- C 52 g
- D 39 g
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
NDA2023
A liquid is heated up to a certain temperature. Which one of the following situation would correspond to the boiling of the liquid ?
- A When atmospheric pressure becomes equal to the vapour pressure ✓
- B When atmospheric pressure becomes less than vapour pressure
- C When atmospheric pressure becomes higher than the vapour pressure
- D When vapour pressure becomes equal to the air pressure
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
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