Supplying heat at constant pressure to a gas leads to________________?
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Answer: D. raising its temperature and doing external work
Explanation
Adding heat to a gas at constant pressure increases its molecular kinetic energy. Higher kinetic energy causes the gas molecules to push the boundaries outward. This resulting volumetric expansion performs external work on the surroundings. Constant pressure heating processes are referred to in thermodynamics as isobaric processes. Charles law states that volume is directly proportional to temperature at constant pressure. Work done in an isobaric process equals pressure multiplied by volume change.
Pistons moving inside combustion engine cylinders operate under nearly constant pressure phases. Hot air balloons rise because heating the contained gas causes expansion and work. Industrial boilers rely on constant pressure heat addition to drive turbines. Option A is incomplete because it omits the necessary external work performed. Option B is wrong because pressure remains strictly constant by definition. Option C is incomplete because temperature must also increase alongside volume.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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