Internal energy change in a closed system equals the heat transferred if the reversible process occurs at constant_______________?
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Answer: C. volume
Explanation
First law of thermodynamics applied to a closed system states that heat added equals internal energy change plus work. During a constant volume process, boundary work is zero because volume displacement cannot occur. Therefore, all heat transferred into the closed system directly increases its internal energy. Internal energy is a state property whose change depends only on initial and final temperature states. A reversible constant volume process is also known as an isochoric or isometric thermodynamic process. Specific heat at constant volume multiplies temperature change to calculate this internal energy variation.
Combustion analysis in closed rigid bombs assumes constant volume heat addition to determine fuel heating values. Engine cylinder heat transfer calculations often evaluate constant volume phases during spark ignition. Thermodynamic property tables use constant volume specific heats to evaluate internal energy changes. Constant pressure processes result in enthalpy changes rather than internal energy changes due to boundary work. Constant temperature processes for ideal gases yield zero internal energy change since temperature remains steady. Constant entropy processes involve no heat transfer, making internal energy changes equal negative work done.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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