The thermodynamic efficiency of a heat engine that rejects heat at a rate of 20 mw when heat is supplied to it at a rate of 60 mw is 66.67%.
It is given that,
Rejected heat at the rate of 20 mw and supplied heat a rate of 60 mw.
It is required to find the thermodynamic efficiency of a heat engine.
As we know that
Work Done = Heat Supplied - Heat Rejected
Work Done = 60 mw - 20 mw
Work Done = 40 mw
So the efficiency of heat engine will be:
[tex]\eta=\frac{Work done}{Heat energy supply}[/tex]
[tex]\eta=\frac{40}{60}[/tex]×[tex]100\\[/tex]
η = [tex]\frac{2}{3}[/tex]×[tex]100\\[/tex]
η = 66.67%
Thus, thermodynamic efficiency of a heat engine that rejects heat at a rate of 20 mw when heat is supplied to it at a rate of 60 mw is 66.67%.
Learn more about thermodynamic efficiency here:
https://brainly.com/question/887978
#SPJ4