Master Thermodynamics Principles: Online Quizzes for Engineering Students

Question 1

Which of the following statements accurately describes the Zeroth Law of Thermodynamics?

Accepted Answer

If two systems are in thermal equilibrium with a third system, they are in thermal equilibrium with each other.

Answer

The entropy of an isolated system always increases.

Answer

Heat can only flow from a hotter system to a colder system.

Answer

The internal energy of a system is constant.

Question 2

Which of the following processes is considéréd isentropic?

Accepted Answer

Isothermal expansion of an ideal gas

Answer

Adiabatic compression of an ideal gas

Answer

Isochoric heating of an ideal gas

Answer

Isobaric cooling of an ideal gas

Question 3

How is the Clausius inequality related to the Second Law of Thermodynamics?

Accepted Answer

The Clausius inequality is a mathematical expression of the Second Law.

Answer

The Second Law is a consequence of the Clausius inequality.

Answer

The Clausius inequality and the Second Law are independent concepts.

Answer

The Clausius inequality violates the Second Law.

Question 4

Determine the change in entropy when 1 mole of an ideal gas undergoes isothermal expansion from 1 L to 2 L.

Accepted Answer

R ln 2

Answer

0

Answer

2R ln 2

Answer

R

Question 5

Which of the following statements accurately describes a reversible process?

Accepted Answer

The system returns to its initial state after the process.

Answer

The entropy of the system decreases.

Answer

The entropy of the surroundings increases.

Answer

The process is adiabatic.

Question 6

According to the first law of thermodynamics, which of the following statements is true?

Accepted Answer

Energy can neither be created nor destroyed, only transferred or transformed.

Answer

The entropy of an isolated system always increases over time.

Answer

Heat flows spontaneously from a colder to a hotter object.

Answer

The efficiency of a heat engine is always 100%.

Question 7

Which of the following statements is the Clausius statement of the second law of thermodynamics?

Accepted Answer

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

Answer

The entropy of a closed system always increases over time.

Answer

No process is 100% efficient.

Answer

The temperature of a system cannot be lowered below absolute zero.

Question 8

What is the Gibbs free energy used to determine?

Accepted Answer

The spontaneity of a reaction at constant temperature and pressure.

Answer

The amount of work a system can do.

Answer

The efficiency of a heat engine.

Answer

The entropy of a system.

Question 9

Which of the following is a characteristic of a closed thermodynamic system?

Accepted Answer

It can exchange energy but not matter with its surroundings.

Answer

It can exchange both energy and matter with its surroundings.

Answer

It cannot exchange energy or matter with its surroundings.

Answer

It can exchange matter but not energy with its surroundings.

Question 10

Which of the following processes can be reversed without changing the entropy of the system?

Accepted Answer

An isothermal process

Answer

An adiabatic process

Answer

An isobaric process

Answer

An isochoric process

Question 11

Which of the following is NOT a characteristic of an isothermal process?

Accepted Answer

Entropy changes.

Answer

Temperature remains constant.

Answer

Heat is transferred into or out of the system.

Answer

Work is done by or on the system.

Question 12

What is the fundamental difference between an ideal gas and a real gas?

Accepted Answer

Ideal gases obey the ideal gas law, while real gases do not.

Answer

Real gases obey the ideal gas law, while ideal gases do not.

Answer

Ideal gases have constant specific heats, while real gases do not.

Answer

Real gases have constant specific heats, while ideal gases do not.

Question 13

The Joule-Thomson coefficient measures the change in:

Accepted Answer

Temperature of a gas undergoing a Joule-Thomson expansion.

Answer

Pressure of a gas undergoing a Joule-Thomson expansion.

Answer

Volume of a gas undergoing a Joule-Thomson expansion.

Answer

Entropy of a gas undergoing a Joule-Thomson expansion.

Question 14

Which of the following is NOT an application of the Carnot cycle?

Accepted Answer

Steam turbines

Answer

Refrigeration

Answer

Heat pumps

Answer

Air conditioning

Question 15

The Carnot efficiency of a heat engine is:

Accepted Answer

The maximum possible efficiency of any heat engine operating between two fixed temperatures

Answer

The ratio of the heat input to the heat output

Answer

The ratio of the work output to the heat input

Answer

The efficiency of an ideal heat engine operating in a Carnot cycle

Question 16

Which of the following is not a phase of a pure substance?

Accepted Answer

Plasma

Answer

Solid

Answer

Liquid

Answer

Gas

Question 17

Which of the following is NOT a fundamental law of thermodynamics?

Accepted Answer

Heat spontaneously flows from a colder to a hotter object.

Answer

The total energy of an isolated system is constant.

Answer

The entropy of an isolated system always increases over time.

Answer

No heat engine can operate with 100% efficiency.

Question 18

Which of the following processes is irreversible?

Accepted Answer

A spontaneous process

Answer

An isothermal process

Answer

An adiabatic process

Answer

An isobaric process

Question 19

What is the SI unit of entropy?

Accepted Answer

Joule per Kelvin

Answer

Kelvin per Joule

Answer

Watt per Kelvin

Answer

Kelvin

Question 20

Which of the following systems is considered an open system?

Accepted Answer

A room with a window open to the outside

Answer

A closed container of water

Answer

A sealed thermos flask

Answer

A bicycle pump

Question 21

What is the fundamental relationship between work and energy?

Accepted Answer

Work is a form of energy.

Answer

Energy is a form of work.

Answer

Work and energy are unrelated.

Answer

Work and energy are inversely related.

Question 22

Which of the following is NOT a thermodynamic property?

Accepted Answer

Velocity

Answer

Temperature

Answer

Volume

Answer

Pressure

Question 23

Which of the following is a characteristic of an isothermal process?

Accepted Answer

Temperature remains constant

Answer

Pressure remains constant

Answer

Volume remains constant

Answer

Entropy remains constant

Question 24

Which of the following processes is considered adiabatic?

Accepted Answer

The expansion of a gas in a vacuum

Answer

The compression of a gas in a piston

Answer

The heating of a gas in a sealed container

Answer

The cooling of a gas in a refrigerator

Question 25

The First Law of Thermodynamics states that:

Accepted Answer

Energy can be transferred from one form to another.

Answer

Energy can be created or destroyed.

Answer

Entropy always increases.

Answer

Heat cannot flow spontaneously from a cold to a hot body.

Question 26

Which of the following systems is considered closed?

Accepted Answer

A refrigerator

Answer

An open fire

Answer

A bicycle pump

Answer

A boiling pot

Question 27

The change in internal energy of a system is equal to:

Accepted Answer

Heat added - Work done

Answer

Heat added + Work done

Answer

Work done - Heat added

Answer

Heat added x Work done

Question 28

Which of the following processes is irreversible?

Accepted Answer

Adiabatic compression

Answer

Adiabatic expansion

Answer

Isothermal compression

Answer

Isochoric heating

Question 29

The thermal efficiency of a heat engine is defined as:

Accepted Answer

Work done / Heat added

Answer

Heat added / Work done

Answer

Entropy change / Heat added

Answer

Work done / Entropy change

Question 30

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

Accepted Answer

Entropy of a perfect crystal at absolute zero is zero.

Answer

No work can be extracted from a perfectly efficient heat engine.

Answer

The entropy of the universe always increases.

Answer

Heat cannot flow spontaneously from a cold to a hot body.

Question 31

Entropy is a measure of:

Accepted Answer

The randomness or disorder of a system

Answer

The energy of a system

Answer

The volume of a system

Answer

The temperature of a system

Question 32

Which statement is NOT a law of thermodynamics?

Accepted Answer

Heat always flows from a colder to a hotter object.

Answer

Energy can neither be created nor destroyed.

Answer

Entropy of an isolated system increases over time.

Answer

The total entropy of an isolated system can never decrease.

Question 33

During an isothermal process of an ideal gas, which property remains constant?

Accepted Answer

Temperature

Answer

Pressure

Answer

Volume

Answer

Internal energy

Question 34

During an irreversible process, the entropy change of the system is:

Accepted Answer

Positive

Answer

Zero

Answer

Negative

Answer

Unpredictable

Question 35

A thermodynamic cycle is described as:

Accepted Answer

A series of processes that return a system to its initial state

Answer

A process that occurs in a single direction

Answer

A process that involves the exchange of heat and work

Answer

A process that is irreversible

Question 36

The efficiency of a heat pump is calculated as:

Accepted Answer

The ratio of the heat transferred to the work input

Answer

The ratio of the work input to the heat transferred

Answer

The ratio of the temperature change to the work input

Answer

The ratio of the work input to the temperature change

Question 37

A system undergoes a thermodynamic cycle. What is the net change in internal energy of the system?

Accepted Answer

Zero

Answer

Negative

Answer

Positive

Answer

Cannot be determined without more information.

Question 38

A heat engine operates between two reservoirs at temperatures of 800 K and 300 K. What is the maximum possible efficiency of this engine?

Accepted Answer

62.5%

Answer

50%

Answer

75%

Answer

100%

Question 39

A refrigerator operates with a coefficient of performance (COP) of 3. If the refrigerator removes 1200 J of heat from the cold reservoir, how much work is required to operate the refrigerator?

Accepted Answer

400 J

Answer

3600 J

Answer

900 J

Answer

1200 J

Question 40

Which of the following statements accurately describes an adiabatic process?

Accepted Answer

No heat transfer occurs during the process.

Answer

The temperature of the gas remains constant.

Answer

The work done by the gas is equal to the heat absorbed.

Answer

The internal energy of the gas increases.

Question 41

What is the change in entropy of a system when 100 J of heat is added to the system at a constant temperature of 300 K?

Accepted Answer

0.33 J/K

Answer

300 J/K

Answer

0 J/K

Answer

100 J/K

Question 42

A steam turbine operates with an inlet steam pressure of 10 bar and an outlet pressure of 1 bar. What determines the maximum possible work output per unit mass of steam flow?

Accepted Answer

The turbine's efficiency.

Answer

The pressure difference.

Answer

The steam flow rate.

Answer

The temperature of the steam.

Question 43

Which of the following statements is NOT a valid statement of the second law of thermodynamics?

Accepted Answer

Heat can be completely converted into work in a cyclic process.

Answer

The entropy of an isolated system always increases or remains constant.

Answer

Heat always flows from a hotter body to a colder body.

Question 44

A closed system undergoes a process during which its internal energy decreases by 500 J. If the system absorbs 200 J of heat from the surroundings, what is the work done by the system?

Accepted Answer

-700 J

Answer

700 J

Answer

-300 J

Answer

300 J

Question 45

A reversible process is one that:

Accepted Answer

Can be reversed without leaving any net change in the system or surroundings.

Answer

Is a theoretical ideal that cannot be achieved in practice.

Answer

Always results in an increase in entropy.

Answer

Occurs very slowly.

Question 46

A Carnot cycle consists of four reversible processes. Which of the following is NOT one of these processes?

Accepted Answer

Isobaric expansion

Answer

Isothermal expansion

Answer

Isothermal compression

Answer

Adiabatic expansion

Question 47

Which of the following statements is **incorrect** about entropy?

Accepted Answer

Entropy always decreases in an isolated system.

Answer

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

Answer

Entropy can be transferred between systems.

Answer

Entropy increases during irreversible processes.

Question 48

A heat engine operates between two reservoirs, one at 800 Kelvin and the other at 300 Kelvin. What is the maximum theoretical efficiency of this engine?

Accepted Answer

62.5%

Answer

37.5%

Answer

50%

Answer

100%

Question 49

A closed system undergoes an adiabatic process. Which of the following is always true?

Accepted Answer

No heat transfer occurs between the system and its surroundings.

Answer

The internal energy of the system remains constant.

Answer

The temperature of the system remains constant.

Question 50

A steam turbine operates with steam entering at 10 MPa and 500°C and exiting at 10 kPa and 100°C. What type of thermodynamic process best describes this change?

Accepted Answer

Expansion

Answer

Isothermal

Answer

Isobaric

Answer

Compression

Question 51

A system undergoes a cyclic process. Which of the following statements is **always** true?

Accepted Answer

The change in internal energy of the system is zero.

Answer

The work done by the system is zero.

Answer

The heat transfer to the system is zero.

Question 52

A gas is compressed isothermally. What happens to the entropy of the gas?

Accepted Answer

Entropy decreases.

Answer

Entropy increases.

Answer

Entropy remains constant.

Answer

Entropy cannot be determined without more information.

Question 53

The Clausius inequality states that:

Accepted Answer

The entropy of an isolated system always increases or remains constant.

Answer

The entropy of an open system always increases.

Answer

The entropy of a closed system always decreases.