The second law of thermodynamics can be stated as: no engine can convert into work:
AAny heat absorbed from a reservoir
BAll heat absorbed from a single reservoir
CMechanical work supplied to it
DEnergy from an electrical source
Answer & Solution
Correct answer: B. All heat absorbed from a single reservoir
1. Kelvin–Planck statement: it is impossible to construct an engine that, working in a cycle, produces no effect other than the EXTRACTION of heat from a SINGLE reservoir and the performance of an equal amount of work.
2. Some heat must always be rejected to a lower-temperature reservoir.
3. This rules out any 100 %-efficient single-reservoir engine.
_Source: NCERT Class 11 Physics Ch 11, §11.8 Second Law (Kelvin–Planck)_
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