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Question #42187
The Question
One mole of an ideal gas in a cylinder with a conducting piston of area undergoes a cyclic process . Process is an isothermal expansion at temperature from volume to . Process is isobaric compression at pressure back to volume . Process is isochoric heating back to the initial state 1. The initial pressure is . During the expansion , the piston moves through a magnetic field and experiences a retarding magnetic force , where . The electrical energy from the resulting eddy currents is entirely dissipated as heat into the gas. The magnetic field is zero during and . What is the net heat absorbed by the gas from the external thermostat during the complete cycle?
Options
- A.
- B.
- C.
- 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
Isothermal Process Work|Cyclic Process Geometry|Variable Force Integration
Why This Question Is Tricky
Common Mistakes
This question tests the application of the First Law of Thermodynamics in a non-conservative hybrid system.
The classic trap is assuming that the net heat absorbed from the thermal reservoir (thermostat) in a cyclic process strictly equals the area enclosed by the P-V diagram ().
Students often overlook that the total heat entering the gas includes both the heat from the thermostat and the internal Joule heating generated by the non-conservative magnetic damping force ().
By failing to account for the mechanical work converted into heat via eddy currents, students incorrectly equate directly to , leading to the trap answer.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Thermodynamics - Class 11 Part 2 |
| Concept | Isothermal Process Work |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |