AP Physics 2: Algebra-Based Practice Quiz: Entropy and the Second Law of Thermodynamics
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Test your understanding with short quizzes. This quiz has 10 questions to check your progress.
Question 1 of 10
All Questions (10)
A) It must always increase at a constant rate.
B) It must always decrease.
C) It can never decrease.
D) It must remain exactly constant.
Correct Answer: C
The provided text explicitly states, 'The second law of thermodynamics states that the total entropy of an isolated system can never decrease...'. It may increase or remain constant, but it cannot go down.
A) The total kinetic energy of particles in a system.
B) The tendency of energy to spread out or become dispersed.
C) The total heat transferred into or out of a system.
D) The efficiency of a system in converting heat to work.
Correct Answer: B
The content states, 'Entropy can be qualitatively described as the tendency of energy to spread or the unavailability of some of the system's energy to do work.' Option B directly reflects the 'tendency of energy to spread'.
A) It must be an isolated system undergoing a reversible process.
B) It is a direct violation of the second law of thermodynamics.
C) It cannot be an isolated system.
D) It must be an open system that is also losing matter.
Correct Answer: C
The text states that the entropy of an *isolated* system never decreases. However, it also clarifies that the entropy of a *closed* system can decrease. Therefore, if a system's entropy is observed to decrease, it cannot be an isolated system.
A) When the system is at absolute zero.
B) When the system undergoes only reversible processes.
C) When energy is continuously removed from the system.
D) When the system is in a state of perfect order.
Correct Answer: B
The content specifies that the entropy of an isolated system 'is constant only when all processes the system undergoes are reversible.'
A) The total energy of the system decreases.
B) All of the system's energy becomes available to do work.
C) More of the system's energy becomes unavailable to do work.
D) The system's energy becomes more concentrated.
Correct Answer: C
The text provides a qualitative description of entropy as 'the unavailability of some of the system's energy to do work.' Therefore, an increase in entropy corresponds to an increase in this unavailability.
A) Processes in closed systems are always reversible.
B) Closed systems can exchange energy with their surroundings.
C) Isolated systems are, by definition, always at maximum entropy.
D) Closed systems do not obey the second law of thermodynamics.
Correct Answer: B
The provided text directly states that 'the entropy of a closed system can decrease because energy can be transferred into or out of the system,' which is an exchange of energy with the surroundings.
A) The entropy of a block of ice decreases as it is cooled further in a freezer (a closed system).
B) The total entropy of a sealed, perfectly insulated container decreases spontaneously.
C) The entropy of an isolated system remains constant during a theoretical, perfectly efficient process.
D) The entropy of one part of an isolated system decreases while another part's entropy increases by a larger amount.
Correct Answer: B
A sealed, perfectly insulated container is an isolated system. The core statement of the second law provided is that the total entropy of an isolated system can never decrease. A spontaneous decrease would be a direct violation of this principle.
A) For any process in an isolated system, the change in total entropy must be greater than or equal to zero.
B) A decrease in a system's entropy is possible if it is a closed system.
C) The entropy of an isolated system must always increase, regardless of the process.
D) An increase in entropy can be described as an increase in the spreading of a system's energy.
Correct Answer: C
This statement is incorrect because the text specifies that entropy is 'constant only when all processes the system undergoes are reversible.' Therefore, it does not *always* increase; it can remain constant under this specific condition.
A) The total entropy of the universe is constant because energy is conserved.
B) The total entropy of the universe is continuously decreasing.
C) The total entropy of the universe does not decrease.
D) The change in the universe's entropy is unpredictable.
Correct Answer: C
The text states that for an isolated system, entropy can never decrease. Since the universe can be considered the ultimate isolated system, its total entropy can only increase or remain constant, but it will never decrease.
A) The ability to transfer energy.
B) The ability to transfer matter.
C) The types of processes that can occur within them.
D) The initial temperature of the system.
Correct Answer: A
The text explicitly states, '...the entropy of a closed system can decrease because energy can be transferred into or out of the system.' This ability to transfer energy is the key distinction from an isolated system in this context.