According to Kelvin-Plank's statement of second law of thermodynamics

Question

Question

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WBPSC JE Mechanical 2018 Official Paper

it is impossible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work.
it is possible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work.
it is impossible to construct a device which operates in a cyclic process and produces no effect other than transfer of heat from a cold body to a hot body.
None of the above

Answer 1

Explanation:

Kelvin-Planck's statement:

It is impossible for any system to operate in a cycle and deliver a net amount of energy by work to its surroundings while receiving energy by heat from a single thermal reservoir.
This implies it is impossible to build a heat engine whose thermal efficiency is 100% and it is known as PMM-II.
It gives the relationship for conversion of heat into work.

F1 Sumit Madhu 17.08.20 D 2

QH = Qinput, W = Woutput

\(\eta\ =\ \frac{W_{output}}{Q_{input}}\) = 100%

The above efficiency is not possible according to PPM-II and Kelvin-Planck's law

Additional Information

Clausius statement:

It is impossible for any system to operate in such a way that the sole result would be an energy transfer by heat from a cooler body to a hotter body.
This implies it is impossible to construct a refrigerator that operates without an input of work.

F1 Sumit Madhu 17.08.20 D 1