What determines the direction of heat flow?
A)Heat always flows from a lower-temperature substance into a higher-temperature substance.
B)Heat always flows from a higher-temperature substance into a lower-temperature substance.
C)Heat flow direction depends upon the density of the substances involved.
D)The direction of heat flow is not predictable in any given process.

Question

Quizplus · Accepted Answer

Heat always flows from a higher-temperature substance into a lower-temperature substance. This is known as the Second Law of Thermodynamics. This law states that heat flows from hot to cold objects or systems as a result of the random motion of molecules and the tendency of higher energy particles to move towards regions of lower energy. This is what causes the transfer of thermal energy from one object to another.

What Determines the Direction of Heat Flow