Verified Solution • 2025–26 Session moderate

QPage 60: Q3: HC Verma: Concepts of Physics - Volume 2 Laws of Thermodynamics Page 60: Q3 Solution: A cylinder containing a gas is lifted from the first floor to…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often think that lifting the cylinder does work on the gas, but the gas only does work on the piston as it expands. The external agent lifts the piston, not the gas itself, so the work done on the gas is zero. Remember that the work done on the gas is $W_{ ext{on}}=-P_{ ext{ext}}Delta V$, which vanishes when the external pressure remains effectively constant during the lift.

A cylinder containing a gas is lifted from the first floor to the second floor. What is the amount of work done on the gas? What is the amount of work done by the gas? Is the internal energy of the gas increased? Is the temperature of the gas increased?

Step-by-Step Verified Solution

**Answer:** Work done on the gas = 0. Work done by the gas = PΔVP\Delta V (positive). Internal energy and temperature changes depend on the nature of the walls. **Step-by-Step Explanation:** When the cylinder is lifted, atmospheric pressure decreases slightly, so the gas expands. Work done **on** the gas is zero; work is done **by** the gas. Work done by the gas W=PΔVW = P\Delta V (positive, since ΔV>0\Delta V > 0). Whether internal energy and temperature increase depends on whether the cylinder walls are **conducting** (heat exchange possible) or **insulating** (adiabatic). Without knowing this, we cannot determine the change in UU or TT [citation:8][citation:10].

All Questions in this Chapter

QPage 60: Q1 QPage 60: Q2 QPage 60: Q3 QPage 60: Q4 QPage 60: Q5 QPage 60: Q6 QPage 60: Q7 QPage 60: Q8 QPage 60: Q9 QPage 60: Q10 QPage 60: Q11 QPage 60: Q12 QPage 60: Q13 QPage 60: Q14 QPage 60: Q15 QPage 61: Q1 QPage 61: Q2 QPage 61: Q3 QPage 61: Q4 QPage 61: Q5 QPage 61: Q6 QPage 61: Q7 QPage 61: Q8 QPage 61: Q9 QPage 61: Q10 QPage 61: Q11 QPage 62: Q12 QPage 62: Q13 QPage 62: Q14 QPages 62-64: Q1 QPages 62-64: Q2 QPages 62-64: Q3 QPages 62-64: Q4 QPages 62-64: Q5 QPages 62-64: Q6 QPages 62-64: Q7 QPages 62-64: Q8 QPages 62-64: Q9 QPages 62-64: Q10 QPages 62-64: Q11 QPages 62-64: Q12 QPages 62-64: Q13 QPages 62-64: Q14 QPages 62-64: Q15 QPages 62-64: Q16 QPages 62-64: Q17 QPages 62-64: Q18 QPages 62-64: Q19 QPages 62-64: Q20 QPages 62-64: Q21 QPages 62-64: Q22

Related Learning Resources & Exam Preparation

Chapter Practice Bank
Practice all topic-wise questions from Laws of Thermodynamics
Reference Textbook Solutions
Explore complete chapter exercises for HC Verma: Concepts of Physics - Volume 2
Competitive PYQ Question Bank
Browse year-wise authentic previous years' questions with solutions
Authentic CBT Mock Tests
Simulate official exam environment with live timer and percentile scoring