Second Law of Thermodynamics Quiz: Test Your Understanding

Question 1

Which of the following processes is considered irreversible?

Accepted Answer

Stretching a rubber band

Answer

Melting ice at 0°C

Answer

Boiling water at 100°C

Answer

Compressing an ideal gas

Question 2

Which of the following units is used to measure entropy?

Accepted Answer

Joules per Kelvin

Answer

Kelvin per Joule

Answer

Watts per Kelvin

Answer

Kelvin per Watt

Question 3

Summarize the Second Law of Thermodynamics in a concise statement.

Accepted Answer

Entropy always increases.

Answer

Heat always flows from hot to cold.

Answer

All processes are irreversible.

Answer

The efficiency of a heat engine can never be 100%.

Question 4

Which statement violates the Second Law of Thermodynamics?

Accepted Answer

Heat engines can achieve 100% efficiency.

Answer

Entropy increases in isolated systems.

Answer

Heat cannot flow spontaneously from cold to hot.

Answer

Irreversible processes always decrease entropy.

Question 5

Which of the following is a statement of the Second Law of Thermodynamics, as formulated by Clausius?

Accepted Answer

The entropy of an isolated system always increases over time.

Answer

Heat can flow spontaneously from a colder body to a hotter body.

Answer

It is impossible to construct a heat engine that operates with 100% efficiency.

Answer

The change in entropy of a system is always positive.

Question 6

What is the efficiency of a Carnot cycle operating between two reservoirs at temperatures T1 and T2?

Accepted Answer

1 - T2 / T1

Answer

T1 / T2

Answer

T2 / T1

Answer

1 - T1 / T2

Question 7

What is the change in entropy of a closed system undergoing a reversible process?

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Cannot be determined

Question 8

What is the physical meaning of entropy?

Accepted Answer

A measure of disorder

Answer

A measure of energy

Answer

A measure of temperature

Answer

A measure of volume

Question 9

Which of the following is a consequence of the Second Law of Thermodynamics?

Accepted Answer

The universe is constantly becoming more disordered.

Answer

The universe is constantly becoming more ordered.

Answer

The universe is in a state of equilibrium.

Answer

The universe is expanding.

Question 10

Which of the following is the Kelvin-Planck statement of the Second Law of Thermodynamics?

Accepted Answer

It is impossible to construct a heat engine that operates with 100% efficiency.

Answer

The entropy of an isolated system always increases over time.

Answer

Heat cannot flow spontaneously from a colder body to a hotter body.

Answer

The change in entropy of a system is always negative.

Question 11

The Carnot cycle is:

Accepted Answer

A theoretical heat engine that operates reversibly.

Answer

A practical heat engine that operates irreversibly.

Answer

A thermodynamic cycle that describes the operation of a steam engine.

Answer

A cycle that describes the operation of a refrigerator.

Question 12

Which of the following is a measure of the randomness or disorder of a system?

Accepted Answer

Entropy

Answer

Energy

Answer

Temperature

Answer

Volume

Question 13

Which of the following is the statement of the Second Law of Thermodynamics proposed by Kelvin-Planck?

Accepted Answer

No heat engine operating between two reservoirs can convert all the heat it absorbs into work.

Answer

Heat flows spontaneously from hotter to colder objects.

Answer

The entropy of an isolated system always increases.

Question 14

The unit of entropy is:

Accepted Answer

Joules per Kelvin (J/K).

Answer

Joules per second (J/s).

Answer

Kelvin (K).

Answer

Watts per meter-Kelvin (W/mK).

Question 15

The efficiency of a Carnot engine is determined by:

Accepted Answer

The temperature difference between the hot and cold reservoirs.

Answer

The volume of the working fluid.

Answer

The type of heat transfer process.

Answer

The speed of the engine.

Question 16

An example of an irreversible process is:

Accepted Answer

Mixing of two different gases.

Answer

Expansion of an ideal gas into a vacuum.

Answer

Adiabatic compression of a gas.

Answer

Heat transfer through a conduction rod.

Question 17

A consequence of the Second Law of Thermodynamics is that:

Accepted Answer

Perpetual motion machines are impossible.

Answer

Entropy always decreases over time.

Answer

The universe is constantly expanding.

Answer

Energy can be created or destroyed.

Question 18

Which statement best represents the Kelvin-Planck formulation of the Second Law of Thermodynamics?

Accepted Answer

It is impossible to construct a heat engine that operates without rejecting heat to a colder reservoir.

Answer

The entropy of an isolated system always increases over time.

Answer

No process can have an efficiency greater than that of a reversible heat engine operating between the same two temperatures.

Question 19

For a heat engine to operate reversibly, what condition must be met?

Accepted Answer

Heat transfer between the engine and its reservoirs must occur infinitely slowly.

Answer

The engine must operate at constant pressure.

Answer

The engine must operate at constant volume.

Question 20

Which system typically possesses the highest entropy?

Accepted Answer

A gas at high temperature and low pressure

Answer

A solid at low temperature and low pressure

Answer

A solid at low temperature and high pressure

Answer

A liquid at high temperature and high pressure

Question 21

Which statement is NOT a consequence of the Second Law of Thermodynamics?

Accepted Answer

Heat can be fully converted into work without any losses.

Answer

Entropy increases in any isolated system that is not at equilibrium.

Answer

Spontaneous processes tend to proceed from states of higher to lower entropy.

Question 22

How is entropy related to disorder?

Accepted Answer

Entropy is a measure of the disorder or randomness of a system.

Answer

Entropy decreases as the disorder of a system increases.

Answer

Entropy is double the disorder of a system.

Answer

Entropy is independent of the disorder of a system.