NEET UG 2020 · Physics · Question 141
NEET 2020 Physics, question 141
Question 141 of the NEET 2020 paper (code E1) is a Physics question from Thermodynamics. Its idea, First Law in Free Expansion, was asked only this once in NEET 2017–2026. The NTA final answer key gives option 2.
Updated 2026-10-08
Q141 · Physics
Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stop cock is suddenly opened. The process is :
- 1isothermal
- 2adiabaticOfficial answer
- 3isochoric
- 4isobaric
Official answer: option 2 · NTA final answer key
Same idea
The only question on First Law in Free Expansion
No other NEET paper from 2017–2026 tested this exact idea.
First Law in Free Expansion: every question and how it was framed
The chapter
Thermodynamics in ten years of NEET
32 questions from 2017–2026, asked in 10 of 10 papers, about 3.1 a paper. Laws of Thermodynamics alone had 10.