Question

two samples of carbon come into contact. a heat transfer will occur between sample a and sample b. what must be true for heat to transfer from sample a to sample b?
the average kinetic energy of a is greater than that of b.
the average kinetic energy of b is greater than that of a.
the average kinetic energy of both samples is equal.
the average kinetic energy does not determine the direction of heat transfer.

Explanation:

Step1: Recall heat - transfer principle

Heat transfers from a hotter object to a colder one.

Step2: Relate temperature and kinetic energy

Temperature is a measure of the average kinetic energy of particles. Higher average kinetic energy means higher temperature.

Step3: Determine heat - transfer direction

Heat will transfer from the sample with higher average kinetic energy (higher temperature) to the sample with lower average kinetic energy (lower temperature). So for heat to transfer from sample A to sample B, the average kinetic energy of A must be greater than that of B.

Answer:

A. The average kinetic energy of A is greater than that of B.