Question

the metal aluminum coils in an air conditioner conduct thermal energy from inside the house and release it outside the house. what can be said about the coils when they are accepting the heat inside the house?
they must be warmer than the air inside the house.
they must be cooler than the air inside the house.
they must have more thermal energy than the air inside the house.
they must be more insulated than the air inside the house.

Explanation:

Heat transfer occurs from a region of higher temperature to a region of lower temperature. For the aluminum coils to accept heat from inside the house, the coils must be at a lower temperature (cooler) than the air inside the house. If they were warmer (option 1), heat would flow from the coils to the house air, not the other way around. Thermal energy content (option 3) is not the determining factor for heat transfer direction; it's temperature. Insulation (option 4) would prevent heat transfer, which is the opposite of what the coils do (conduct heat).

Answer:

They must be cooler than the air inside the house.