question_answer

Explain why it is impossible to design a heat engine with 100% efficiency. Or Even Carnot engine cannot have 100% efficiency. Explain, why?    

Answer:

                Efficiency, \[\eta =1-\frac{{{T}_{2}}}{{{T}_{1}}}\] The efficiency will be 100% or 1, if\[{{T}_{2}}=0K\]. Since, temperature equal to \[0\text{ K}\]cannot be realised, a heat engine with \[\text{1}00%\] efficiency cannot be designed.