In a household refrigerator, thermal energy is continually removed from the 5∘C interior compartment and expelled to the 25∘C kitchen air. Which statement best accounts for this apparent transfer of energy from a colder region to a hotter one?
(a) Because the temperature difference is small, the usual direction of heat flow can reverse without additional energy.
(b) Metals conduct heat more efficiently at lower temperatures, so the refrigerator’s coils naturally draw energy from the cold interior to the warmer room.
(c) Work done by the compressor supplies energy that pumps thermal energy from the 5∘C compartment to the 25∘C room.
(d) The interior air has a smaller heat capacity, allowing its energy to leak outward until equilibrium is reached.