Donna Flynn

2022-07-17

An imaginary machine takes 9,000J of heat from a hot reservoir and 3,000 J of heat from a cold reservoir and produces 12,000 J of work. What can be said about this machine? O It violates both the first and second laws of thermodynamics. It violates the second law of thermodynamics but not the first law. It violates the first law of thermodynamics but not the second law. O It does not violate either the first or the second law of thermodynamics.

Minbutastc

Expert

Given :
An imaginary machine takes 9,000 J of heat from a hot reservoir and 3,000 J of heat from a cold reservoir and produce 12,000 J of work.
Means energy is conserved.
On the basis of this we can find the correct statement , which is given in step 2
Option (ii) is correct. i.e., It violates the second law of thermodynamics but not the first law. According to first law of thermodynamics " Energy is conservative quantity" . Here also energy remain conserved (9,000 J+3,000 J =12,000 J). So it does not violate first law. But for the second law: It is impossible to make a cyclically operating device, the sole effect of which is to absorb energy in the form of heat from a single thermal reservoir and to deliver an equivalent amount of work. Also it is impossible for an engine to extract heat from cold reservoir without any help of external agency. Here we get equivalent amount of work done. So second law is violating.

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