Which one is incorrect statement of the second law of thermodynamics ?

Question

Which one is incorrect statement of the second law of thermodynamics ? (A) It is impossible for a cyclic process to transfer heat from a system at a lower temperature to one at a higher temperature without converting some work to heat (B) It is impossible to convert heat completely into equivalent amount of work without producing changes elsewhere (C) Every perfect machine working reversibly between the same temperatures of source and sink has the same efficiency whatever be the nature of the substance used (D) Heat engines can be made 100% efficient

Tardigrade Admin · Accepted Answer

A heat engine cannot have 100% efficiency.

Q. Which one is incorrect statement of the second law of thermodynamics ?

It is impossible for a cyclic process to transfer heat from a system at a lower temperature to one at a higher temperature without converting some work to heat

It is impossible to convert heat completely into equivalent amount of work without producing changes elsewhere

Every perfect machine working reversibly between the same temperatures of source and sink has the same efficiency whatever be the nature of the substance used

Heat engines can be made 100% efficient

A heat engine cannot have 100% efficiency.