During an isothermal process, the internal energy of the gas molecules________________?
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Answer: C. remains constant
Explanation
Since temperature is constant during an isothermal process, internal energy of an ideal gas remains constant. Internal energy depends exclusively on temperature for ideal gases in thermodynamic systems. Any heat added to the system is entirely converted into boundary work output. Isothermal processes occur very slowly to allow heat transfer with thermal reservoirs. Joule's law established that internal energy changes depend only on temperature fluctuations. The product of pressure and volume remains constant throughout an isothermal ideal gas process.
Slow compression or expansion processes in well-cooled cylinders approximate isothermal conditions. Thermodynamic cycle analysis often combines isothermal stages with adiabatic processes. Engineers account for heat exchange requirements to maintain near-constant temperatures. Option A is incorrect because internal energy cannot increase without a temperature rise. Option B is false since temperature does not decrease during an isothermal process. Option D incorrectly assumes unpredictable behavior for standard ideal gas energy states.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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