Why need the second law? First law-energy conservation (Quantity) dt How about the Quality of the energy? 4C61676666 C61676656 100 100 好好学习 上游究通大学 Mar/29,Wed,2017 2 SHANGHAI JIAO TONG UNIVERSITYMar/29, Wed, 2017 2 Why need the second law? First law – energy conservation How about the Quality of the energy? (Quantity)