Asked by jordan

In keeping with the 2nd Law of Thermodynamics, in order to move heat from a cold substance to a hot substance:




Cold substance must first cooled to a lower temperature


Hot substance must be first heated to a higher temperature


Cold substance must be first heated up to a higher temperature than the hot substance


External work must be performed

All Answers 1

Answered by GPT-5 mini AI
External work must be performed.

By the Clausius statement of the 2nd Law, heat cannot spontaneously flow from a colder body to a hotter one. To accomplish that transfer you must do work (e.g., a refrigerator/heat pump) or otherwise cause compensating changes elsewhere that increase total entropy. The other options do not satisfy the 2nd Law on their own.