Question

heat moves from _____ to _____ places. a. hot; hotter b. colder; cold c. colder; hotter d. hotter; colder

Answer 1

Answer: Option (d) is the correct answer.

Explanation:

When we place two objects of different temperature adjacent to each other then there will occur transfer of heat from hotter object to colder object till their temperature becomes equal.

This process is known as conduction.

For example, a metal spoon placed in hot coffee cup then heat will flow from coffee to the cup.

Therefore, we can conclude that heat moves from hotter to colder places.

Answer 2

D. Heat moves spontaneously only from cold objects to hotter ones.

The entropy of a system measures its orderlessness. The greater the number of ways of energy distribution in a system, the greater its entropy. Temperature measures the average kinetic energy of particles within an object. Allowing two object of different temperature to come into contact and undergo heat exchange would thus induce a redistribution of energy between the two objects. Moving the "heat" from the colder object to the hotter one would force the energy into a smaller space than moving "heat" in the opposite direction would. As a result, the sum of entropy of the two objects would decrease if the colder object experience a decrease in temperature while the hotter one an increase in temperature, whereas cooling the hotter object while heating the colder object would increase lead to an increase in the entropy.

By the second law of thermodynamics, isolated systems with no heat exchange with their surroundings experience only spontaneous decrease but not increase in their entropy. As a result, only the transfer of heat from hotter objects to colder ones can be spontaneous.