Question

what temperature is required to transfer waste heat to the environment for a heat engine to be 100 percent efficient

Answer 1

The temperature required for a heat engine to be 100 percent efficient is absolute zero, but this is not achievable in practice due to the second law of thermodynamics. The maximum efficiency a heat engine can achieve is given by the Carnot efficiency, which depends on the temperatures of the hot and cold reservoirs.

Step-by-step explanation:

The temperature required to transfer waste heat to the environment for a heat engine to be 100 percent efficient is absolute zero (0 Kelvin or -273.15 degrees Celsius).

This is because according to the second law of thermodynamics, it is impossible for a heat engine to be 100 percent efficient since some heat will always be transferred to the environment as waste heat.

In practical terms, the maximum efficiency a heat engine can achieve is given by the Carnot efficiency, which depends on the temperatures of the hot and cold reservoirs.

Answer 2

A heat engine has three components namely the heat source, the heat sink and the object where the work is done. Heat engines are used to convert heat to work. A 100% percent efficiency means all heat energy is converted into work energy. This means there is no heat lost to the heat sink. So, in this situation, the temperature should still stay the same. However, this cannot be done. A heat lost is needed in order for the heat engine to keep running continuously. Thus, in reality, a 100% efficiency is impossible.