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Question #42191
The Question
A vertical cylindrical container with adiabatic walls contains moles of a monatomic ideal gas. It is fitted with a frictionless, adiabatic piston of mass and cross-sectional area . The atmospheric pressure is , and it is given that . Initially, the container is placed in an elevator accelerating upwards with an acceleration (where is the acceleration due to gravity). The gas is in thermal and mechanical equilibrium with an initial volume . Suddenly, the elevator's acceleration drops to zero and it continues to move with a constant upward velocity. The gas expands and eventually reaches a new equilibrium state with volume . Find the ratio .
Options
- A.
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- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Intuition_Breaker
Train your brain to resist "obvious" answers that are designed to deceive your intuition.
Concepts Behind This Question
Adiabatic Process Constraint|Frame of Reference|Newton’s Laws
Why This Question Is Tricky
Common Mistakes
This question tests the student's ability to distinguish between reversible and irreversible adiabatic processes in a non-inertial frame.
The trap lies in blindly applying the standard reversible adiabatic equation () when the external pressure changes abruptly due to a sudden change in the frame's acceleration.
The sudden change in the pseudo-force alters the effective weight of the piston, making the expansion irreversible against a new, constant external pressure.
Students who fail to recognize this will incorrectly use the reversible relation, ignoring that the boundary work term is governed by the modified non-inertial constraint.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Thermodynamics - Class 11 Part 2 |
| Concept | Adiabatic Process Constraint |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |