ahyaa Posted January 29, 2014 Share Posted January 29, 2014 According to the second law of thermodynamics, it is impossible for: heat energy to flow from a colder body to a hotter bodyan ideal heat engine to have the efficiency of 99%an ideal heat engine to have non-zero power.a physical process to yield more energy than what is put in ^As taken from a homework problem, the explanation: The ideal engine follows a reversible cycle--therefore, an infinitely slow one. If the work is being done at the infinitely slow rate, the power of such an engine is zero. An alternative way to state the second law of thermodynamics is as follows: It is impossible to construct a cyclical heat engine whose sole effect is the continuous transfer of heat energy from a colder object to a hotter one. This statement is known as Clausius statement of the second law. Note the word "sole." Of course, it is possible to construct a machine in which a heat flow from a colder to a hotter object is accompanied by another process, such as work input. Is anyone able to explain this in layman terms, i.e. to an first-level college physics student... Link to comment Share on other sites More sharing options...
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!Register a new account
Already have an account? Sign in here.Sign In Now