Master Thermodynamics Fundamentals: Online Quizzes and Resources

Question 1

Which of the following is **not** a type of thermodynamic system?

Accepted Answer

Adiabatic system

Answer

Open system

Answer

Closed system

Answer

Isolated system

Question 2

Which of the following is a key characteristic of an open thermodynamic system?

Accepted Answer

Exchanges both energy and matter with the surroundings

Answer

Exchanges energy but not matter with the surroundings

Answer

Does not exchange energy or matter with the surroundings

Answer

Exchanges matter but not energy with the surroundings

Question 3

Which of the following is not classified as a type of thermodynamic system?

Accepted Answer

The universe

Answer

Isolated system

Answer

Closed system

Answer

Open system

Question 4

Which of the following is not considered a thermodynamic process?

Accepted Answer

Chemical reaction

Answer

Isothermal process

Answer

Adiabatic process

Answer

Isobaric process

Question 5

Which principle of thermodynamics states that the total energy of an isolated system remains constant?

Accepted Answer

Conservation of Energy

Answer

Increase in Entropy

Answer

Heat Transfer

Answer

Carnot's Theorem

Question 6

According to the first law of thermodynamics, what happens to the total energy in an isolated system?

Accepted Answer

It can be transferred or transformed, but not created or destroyed.

Answer

It can be created or destroyed.

Answer

It can be increased by more than 100%.

Answer

It always increases over time.

Question 7

What is the defining characteristic of an isentropic process?

Accepted Answer

Entropy remains constant.

Answer

Entropy decreases.

Answer

Entropy increases.

Answer

Entropy is undefined for isentropic processes.

Question 8

Which of the following is **not** a thermodynamic property of a system?

Accepted Answer

Mass

Answer

Temperature

Answer

Volume

Answer

Entropy

Question 9

In an isothermal process of a closed thermodynamic system, what occurs to the system's internal energy?

Accepted Answer

Remains constant

Answer

Increases

Answer

Decreases

Answer

Varies based on the specific process

Question 10

In thermodynamics, entropy refers to which of the following?

Accepted Answer

The degree of disorder or randomness within a system

Answer

The amount of energy contained within a system

Answer

The temperature of a system

Answer

The volume occupied by a system

Question 11

Which of the following is NOT a thermodynamic property?

Accepted Answer

Mass

Answer

Temperature

Answer

Volume

Answer

Pressure

Question 12

According to Clausius's statement of the second law of thermodynamics, what occurs to the entropy of an isolated system over time?

Accepted Answer

It steadily increases.

Answer

It steadily decreases.

Answer

It stays the same.

Answer

It changes unpredictably.

Question 13

Which statement accurately describes the first law of thermodynamics?

Accepted Answer

The first law of thermodynamics expresses the conservation of energy.

Answer

Energy can be freely converted between heat and work.

Answer

Heat entering a system always raises its internal energy.

Answer

The first law of thermodynamics applies to all systems, regardless of size or complexity.

Question 14

In a closed thermodynamic system undergoing a cyclic process, what is the net work done by the system?

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Equal to the heat added to the system

Question 15

In a closed thermodynamic system undergoing a reversible process, what is the relationship between heat transfer into the system and work done by the system?

Accepted Answer

Heat transfer into the system equals work done by the system.

Answer

Heat transfer into the system is greater than work done by the system.

Answer

Heat transfer into the system is less than work done by the system.

Answer

Heat transfer into the system and work done by the system are unrelated.

Question 16

Which of the following characterizes an isentropic process?

Accepted Answer

Constant entropy

Answer

Increasing entropy

Answer

Decreasing entropy

Answer

Either increasing or decreasing entropy

Question 17

Which attribute describes a closed thermodynamic system?

Accepted Answer

It allows the exchange of energy but not mass with its surroundings.

Answer

It allows the exchange of mass but not energy with its surroundings.

Question 18

An engine operates between two reservoirs at temperatures T_1 and T_2, where T_1 is greater than T_2. Which of the following statements about the engine's efficiency, η, is correct?

Accepted Answer

η = (T_1 - T_2) / T_1

Answer

η = 100%

Answer

η is independent of the working fluid used in the engine.

Question 19

Which of the following is an example of a closed thermodynamic system?

Accepted Answer

A sealed bottle containing water

Answer

A bicycle pump connected to a flat tire

Answer

A steam turbine operating in a power plant

Answer

A car engine running on gasoline

Question 20

What is the best definition of a thermodynamic system?

Accepted Answer

A specific region of space where energy and matter can be exchanged.

Answer

A group of molecules interacting through chemical reactions.

Answer

A sealed container that prevents the exchange of both energy and matter.

Answer

A system that is isolated from its surroundings and maintains a constant internal energy.

Question 21

Which statement about the second law of thermodynamics is **incorrect**?

Accepted Answer

All processes are reversible according to the second law.

Answer

Entropy in an isolated system always increases.

Answer

Entropy measures the randomness or disorder of a system.

Answer

The second law predicts the direction of spontaneous processes.

Question 22

In an isothermal process, the change in internal energy (ΔU) of a closed system is directly proportional to the work done (W) by the system. Which equation accurately represents this relationship?

Accepted Answer

ΔU = W

Answer

ΔU > W

Answer

ΔU < W

Answer

ΔU is not related to W

Question 23

Within a closed thermodynamic system, which processes will lead to an increase in entropy?

Accepted Answer

Adiabatic expansion

Accepted Answer

Isochoric heating

Answer

Isothermal compression

Answer

Isobaric cooling

Question 24

A closed system undergoes a reversible isothermal process from state 1 to state 2. What happens to the entropy of the system?

Accepted Answer

Remains constant

Answer

Decreases

Answer

Increases

Question 25

In an isentropic process of a closed thermodynamic system, what is the relationship between the change in entropy and the change in internal energy?

Accepted Answer

Entropy change is zero, while internal energy change can be non-zero.

Answer

Entropy change equals internal energy change.

Answer

Entropy change is proportional to internal energy change.

Answer

Entropy change is non-zero, while internal energy change is zero.

Question 26

In which engineering discipline is thermodynamics most closely linked to the analysis and design of electrical circuits and devices?

Accepted Answer

Electrical engineering

Answer

Chemical engineering

Answer

Mechanical engineering

Answer

Civil engineering

Question 27

Which of the following is the first law of thermodynamics?

Accepted Answer

Energy cannot be created or destroyed during any process.

Answer

Entropy always increases in a closed system.

Answer

Heat flows from cold to hot.

Answer

The efficiency of a heat engine can exceed 100%.

Question 28

What is a measure of the disorder of a system?

Accepted Answer

Entropy

Answer

Enthalpy

Answer

Exergy

Answer

Gibbs free energy

Question 29

The efficiency of a heat engine is expressed as:

Accepted Answer

Work output divided by heat input

Answer

Heat output divided by heat input

Answer

Work input divided by heat output

Answer

Heat input divided by work output

Question 30

The spontaneity of a process is determined by:

Accepted Answer

The change in free energy

Answer

The change in entropy

Answer

The change in enthalpy

Answer

The change in heat capacity

Question 31

At the critical point of a substance, liquid and gas phases become:

Accepted Answer

Indistinguishable

Answer

Distinguishable

Answer

Solid and liquid

Answer

Gas and solid

Question 32

Which of the following is not a law of thermodynamics?

Accepted Answer

All processes are reversible

Answer

Conservation of energy

Answer

Increase of entropy

Answer

Impossibility of creating or destroying energy

Question 33

What is the SI unit of entropy?

Accepted Answer

Joule per Kelvin

Answer

Joule

Answer

Watt

Answer

Kelvin per Joule

Question 34

Which type of thermodynamic system exchanges both heat and work with its surroundings?

Accepted Answer

Open system

Answer

Closed system

Answer

Isolated system

Answer

Reversible system

Question 35

Which process is isothermal?

Accepted Answer

Gas heated at constant volume

Answer

Gas expanding in a vacuum

Answer

Gas compressed in a piston

Answer

Gas cooled at constant pressure

Question 36

Which of the following is a fundamental law of thermodynamics that describes the direction of spontaneous processes?

Accepted Answer

Second law

Answer

Zeroth law

Answer

First law

Answer

Third law

Question 37

Which mathematical expression represents the first law of thermodynamics for a closed system undergoing an arbitrary process?

Accepted Answer

dQ = dU + dW

Answer

dU = dQ - dW

Answer

dQ = dW - dU

Answer

dW = dQ - dU

Question 38

Entropy is defined as:

Accepted Answer

The measure of the disorder of a system

Answer

The amount of heat flowing into a system

Answer

The change in internal energy of a system

Answer

The work done by a system

Question 39

Which of the following systems is considered closed in thermodynamics?

Accepted Answer

A piston-cylinder assembly with adiabatic walls

Answer

A turbine

Answer

A heat exchanger

Answer

An open flame

Question 40

The triple point of a substance is significant because it represents the:

Accepted Answer

Point where the solid, liquid, and gas phases coexist in equilibrium

Answer

Point where the pressure is highest

Answer

Point where the temperature is lowest

Answer

Point where the volume is smallest

Question 41

An isobaric process is one in which:

Accepted Answer

Pressure remains constant

Answer

Volume remains constant

Answer

Temperature remains constant

Answer

Entropy remains constant

Question 42

The Carnot cycle is a theoretical heat engine that:

Accepted Answer

Operates with the maximum possible efficiency

Answer

Produces the most power

Answer

Is the most economical to build

Answer

Has the lowest emissions

Question 43

In an isothermal reversible process, what is the change in entropy of the system?

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Cannot be determined from the provided information

Question 44

Which system type is characterized by the exchange of both matter and energy with its surroundings?

Accepted Answer

Open system

Answer

Closed system

Answer

Isolated system

Answer

Adiabatic system

Question 45

The efficiency of a heat engine operating between two reservoirs with temperatures T1 and T2 is given by:

Accepted Answer

1 - (T1/T2)

Answer

T1 - T2

Answer

T2 - T1

Answer

(T1/T2) - 1

Question 46

Define the specific heat of a substance.

Accepted Answer

The amount of heat required to raise the temperature of 1 kg of the substance by 1 K

Answer

The amount of heat required to raise the temperature of 1 g of the substance by 1 K

Answer

The amount of heat required to raise the temperature of 1 mol of the substance by 1 K

Answer

The amount of heat required to raise the temperature of 1 cm3 of the substance by 1 K

Question 47

Which of the following is not a valid unit of entropy?

Accepted Answer

kWh/kg K

Answer

J/K

Answer

cal/g K

Answer

kJ/mol K

Question 48

What is the SI unit of entropy?

Accepted Answer

Joule per Kelvin

Answer

Joule

Answer

Kelvin

Answer

Kelvin per Joule

Question 49

Which type of system can exchange both heat and mass with its surroundings?

Accepted Answer

Open system

Answer

Closed system

Answer

Isolated system

Answer

Adiabatic system

Question 50

State the first law of thermodynamics.

Accepted Answer

The total energy of an isolated system remains constant

Answer

Heat cannot be transferred from a colder object to a hotter object

Answer

The entropy of an isolated system always increases or remains constant

Answer

The efficiency of a heat engine is always less than 100%

Question 51

What is the maximum efficiency of a heat engine that operates between two reservoirs at different temperatures called?

Accepted Answer

Carnot efficiency

Answer

Thermal efficiency

Answer

Ideal efficiency

Answer

Maximum efficiency

Question 52

According to the second law of thermodynamics, which statement is accurate?

Accepted Answer

Entropy in an isolated system consistently rises or stays the same.

Answer

Heat naturally flows from cold to hot.

Answer

Heat engines can operate with perfect efficiency.

Answer

Biological systems are exempt from the second law of thermodynamics.

Question 53

How can exergy analysis be used to identify and minimize sources of inefficiency in energy systems?

Accepted Answer

By comparing the exergy content of the system at different points, exergy destruction can be identified, indicating sources of inefficiency.

Answer

Maximizing the exergy efficiency of individual components guarantees optimal overall system efficiency.

Answer

Exergy analysis is only applicable to large-scale power plants and not suitable for smaller energy systems.

Answer

Exergy analysis is a purely theoretical concept with no practical applications in real-world energy systems.

Question 54

According to the first law of thermodynamics, energy:

Accepted Answer

Cannot be created or destroyed

Answer

Can be created or destroyed

Answer

Can be created but not destroyed

Answer

Can be destroyed but not created

Question 55

Entropy is a measure of:

Accepted Answer

Disorder

Answer

Heat energy

Answer

Work done

Answer

Temperature

Question 56

A reversible process is one:

Accepted Answer

That can be reversed without any loss of energy

Answer

That cannot be reversed without any loss of energy

Answer

That involves heat transfer

Answer

That involves mass transfer

Question 57

The efficiency of a heat engine is defined as:

Accepted Answer

The ratio of work done to heat input

Answer

The ratio of heat input to work done

Answer

The ratio of heat rejected to work done

Answer

The ratio of work done to heat rejected

Question 58

A pure substance is characterized by:

Accepted Answer

Fixed composition

Answer

Variable composition

Answer

Multiple phases

Answer

Solid state

Question 59

At the critical point of a substance:

Accepted Answer

Liquid and gas phases become indistinguishable

Answer

Solid and liquid phases become indistinguishable

Answer

Gas and solid phases become indistinguishable

Answer

Substance reaches its highest temperature

Question 60

The ideal gas law is applicable to:

Accepted Answer

Ideal gases only

Answer

Real gases at low pressures and high temperatures

Answer

Real gases at any pressure and temperature

Answer

Real gases at high pressures and low temperatures

Question 61

State the correct mathematical expression for the first law of thermodynamics.

Accepted Answer

dU = dQ + dW

Answer

dQ = dU - dW

Answer

dW = dQ - dU

Answer

dQ = dW + dU

Question 62

What is the unit used for measuring entropy in the International System of Units (SI)?

Accepted Answer

Joules per Kelvin

Answer

Newtons per square meter

Answer

Watts per meter

Answer

Pascals per square meter

Question 63

Explain the fundamental difference between heat and work in thermodynamics.

Accepted Answer

Heat is transferred due to a temperature difference, while work is transferred due to a force acting over a distance.

Answer

Heat is transferred due to a force acting over a distance, while work is transferred due to a temperature difference.

Answer

Heat and work are both forms of energy transferred due to temperature differences.

Answer

Heat and work are both forms of energy transferred due to forces acting over distances.

Question 64

Define the Gibbs free energy.

Accepted Answer

The maximum amount of work that can be extracted from a closed system at constant temperature and pressure

Answer

The minimum amount of energy that must be added to a closed system at constant temperature and pressure

Answer

The change in internal energy of a closed system at constant temperature and pressure

Answer

The change in entropy of a closed system at constant temperature and pressure