Introduction to Thermodynamics: Master the Basics of Energy and Heat Transfer

Question 1

Which of the following best describes a practical **application** of the first law of thermodynamics?

Accepted Answer

Determining the efficiency of thermal power plants

Answer

Predicting the direction of chemical reactions

Answer

Analyzing only isolated systems with no energy exchange

Answer

Applying only to ideal gases

Question 2

In an isobaric process, which system property remains constant?

Accepted Answer

Pressure

Answer

Volume

Answer

Temperature

Answer

Internal energy

Question 3

Which of the following accurately describes an isolated thermodynamic system?

Accepted Answer

Exchanges neither energy nor mass with its surroundings

Answer

Exchanges both energy and mass with its surroundings

Answer

Exchanges energy but not mass with its surroundings

Answer

Is in equilibrium with its surroundings

Question 4

Which of the following is NOT a thermodynamic system?

Accepted Answer

A bag of ice melting in a room

Answer

A closed system that exchanges heat with its surroundings

Answer

An isolated system that does not exchange heat or matter with its surroundings

Answer

An open system that exchanges both heat and matter with its surroundings

Question 5

What is the best definition of a thermodynamic system?

Accepted Answer

A defined amount of matter and energy within a boundary

Answer

A space with no matter or energy

Answer

A theoretical concept for studying energy changes

Answer

A sealed container with a set volume of gas

Question 6

Which of the following is NOT a type of thermodynamic system?

Accepted Answer

Control volume

Answer

Closed system

Answer

Open system

Answer

Isolated system

Question 7

Which of the following is NOT a thermodynamic property?

Accepted Answer

Acceleration

Answer

Temperature

Answer

Volume

Answer

Enthalpy

Question 8

In an isothermal process, the temperature of a gas remains constant. Can an isothermal process occur without the gas performing any work?

Accepted Answer

Yes, if the pressure of the gas remains constant.

Answer

Yes, if the volume of the gas decreases.

Answer

No, it is not possible.

Answer

It depends on the initial and final volumes of the gas.

Question 9

In thermodynamics, an isolated system is characterized by which of the following properties?

Accepted Answer

Neither mass exchange nor energy exchange can occur.

Answer

Mass exchange is permitted, but energy exchange is not.

Answer

Mass exchange is not permitted, but energy exchange is.

Answer

Both mass exchange and energy exchange can occur.

Question 10

In a closed system, which process involves adding heat while keeping the volume constant?

Accepted Answer

Isochoric

Answer

Isothermal

Answer

Adiabatic

Answer

Isobaric

Question 11

Which characteristic defines an isochoric process?

Accepted Answer

Volume remains constant

Answer

Pressure remains constant

Answer

Temperature remains constant

Question 12

In thermodynamics, a closed system is defined as a region of space or matter selected for analysis. Which of the following accurately describes a closed system?

Accepted Answer

A system with fixed boundaries that allows the exchange of heat and work, but not mass, with its surroundings.

Answer

A system with fixed boundaries that permits the exchange of both mass and energy with its surroundings.

Answer

A system with no boundaries that allows for the unrestricted exchange of both mass and energy with its surroundings.

Answer

A system with moving boundaries that permits the exchange of only mass, but not energy, with its surroundings.

Question 13

Identify the thermodynamic process that maintains constant pressure.

Accepted Answer

Isobaric

Answer

Isothermal

Answer

Adiabatic

Answer

Isochoric

Question 14

What is the primary focus of thermodynamics?

Accepted Answer

The study of energy and its transformations

Answer

The study of heat transfer only

Answer

The study of the behavior of gases

Answer

The study of the efficiency of machines

Question 15

In an isothermal process applied to an ideal gas, what occurs to its internal energy?

Accepted Answer

Stays the same

Answer

Increases

Answer

Decreases

Question 16

In thermodynamics, what is the key significance of the internal energy 'U' of a system?

Accepted Answer

'U' measures the system's thermal energy, depending solely on its state, not its path.

Answer

'U' represents the system's total energy, which remains constant during any process.

Answer

'U' is an extensive property that is always positive for a given system.

Answer

'U' is the difference between the system's total energy and its potential energy.

Question 17

Which of the following is NOT a thermodynamic system?

Accepted Answer

A specific volume within a fluid flow defined by imaginary boundaries

Answer

A closed system that can exchange heat with the surroundings

Answer

An open system that can exchange both heat and mass with the surroundings

Answer

An isolated system that does not exchange heat or mass with the surroundings

Question 18

Which thermodynamic process involves heat transfer at constant pressure?

Accepted Answer

Isobaric

Answer

Isochoric

Answer

Adiabatic

Answer

Isothermal

Question 19

What is exergy, and why is it important in evaluating the potential and usefulness of energy sources?

Accepted Answer

Exergy is the maximum useful work that can be extracted from a system through a reversible process, indicating the intrinsic quality and availability of energy resources.

Answer

Exergy is the total energy content of a system, regardless of its availability or usefulness.

Answer

Exergy is a theoretical concept with limited practical significance in assessing energy sources.

Question 20

According to the second law of thermodynamics, which statement best describes the relationship between entropy and irreversibility?

Accepted Answer

Entropy measures disorder, and irreversible processes always increase entropy.

Answer

Entropy measures heat transfer, and irreversible processes always decrease entropy.

Answer

Entropy measures energy, and irreversible processes always decrease entropy.

Question 21

In a cyclic process involving isothermal expansion, adiabatic compression, isobaric compression, and adiabatic expansion, what is the net work done by the system?

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Depends on initial and final states

Question 22

Which property describes the amount of heat required to raise the temperature of a substance by one degree?

Accepted Answer

Specific heat capacity

Answer

Thermal conductivity

Answer

Enthalpy

Answer

Entropy

Question 23

In an isothermal process for an ideal gas, which thermodynamic property remains constant?

Accepted Answer

Temperature

Answer

Volume

Answer

Pressure

Answer

Entropy

Question 24

Which of the following processes is considered reversible?

Accepted Answer

Mixing of gases at constant temperature and pressure

Answer

Adiabatic expansion of a gas

Answer

Combustion of fuel

Answer

Friction between two surfaces

Question 25

Under which condition does the entropy of a closed system increase?

Accepted Answer

Heat is added to the system.

Answer

Heat is removed from the system.

Answer

The system undergoes an adiabatic process.

Answer

The system undergoes an isothermal process.

Question 26

The first law of thermodynamics is a statement of:

Accepted Answer

Conservation of energy

Answer

Conservation of mass

Answer

Conservation of momentum

Answer

Conservation of charge

Question 27

Which statement accurately describes the first law of thermodynamics?

Accepted Answer

The change in internal energy of a closed system is equal to the heat added to the system minus the work done by the system.

Answer

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

Answer

The entropy of an isolated system can never decrease.

Answer

The total energy of an isolated system is constant.

Question 28

Which of the following is NOT a state property?

Accepted Answer

Specific heat capacity

Answer

Temperature

Answer

Pressure

Answer

Entropy

Question 29

Which substance can be considered an ideal gas at room temperature and pressure?

Accepted Answer

Air

Answer

Water vapor

Answer

Helium under high pressure

Answer

Carbon dioxide under very low temperature

Question 30

Which process involves no heat transfer between the system and its surroundings?

Accepted Answer

Expansion of an ideal gas into a vacuum

Answer

Compression of an ideal gas in a piston-cylinder

Answer

Heating of an ideal gas at constant pressure

Answer

Cooling of an ideal gas in a closed vessel

Question 31

For a closed system undergoing a reversible process, what is the change in entropy?

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Cannot be determined

Question 32

Which of the following factors does NOT affect the properties of a pure substance?

Accepted Answer

Volume

Answer

Temperature

Answer

Pressure

Answer

Composition

Question 33

Define specific heat capacity and explain how it helps characterize the thermal properties of different substances.

Accepted Answer

The amount of heat energy required to raise the temperature of a unit mass of a substance by 1 K

Answer

The rate at which heat is transferred between two objects in thermal contact

Answer

A measure of a substance's ability to store thermal energy

Answer

The property that determines the boiling point of a substance

Question 34

In air-conditioning systems, why is relative humidity important, and how does it impact human thermal comfort?

Accepted Answer

For optimal comfort, relative humidity should typically be between 40% and 60%.

Answer

Relative humidity is unimportant in air-conditioning systems.

Answer

High relative humidity improves comfort by aiding skin evaporation.

Answer

Relative humidity does not affect the energy efficiency of air-conditioning systems.

Question 35

Which statement below is NOT a fundamental law of thermodynamics?

Accepted Answer

Energy can be created or destroyed.

Answer

Energy is conserved.

Answer

Entropy always increases.

Answer

Heat flows from hotter to colder objects.

Question 36

Define the specific heat capacity of a substance.

Accepted Answer

The amount of heat needed to raise its temperature by 1°C.

Answer

The amount of heat needed to raise its temperature by 1 kJ.

Answer

The ratio of its specific heat to its volume.

Answer

The ratio of its temperature to its specific heat.

Question 37

Identify a closed system from the given options.

Accepted Answer

A sealed bottle of water

Answer

A room with an open window

Answer

A car engine

Answer

A refrigerator

Question 38

What does the enthalpy of a system represent?

Accepted Answer

The sum of its internal energy and pressure

Answer

The sum of its internal energy and volume

Answer

The difference between its internal energy and volume

Answer

The difference between its internal energy and pressure

Question 39

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

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Cannot be determined

Question 40

According to the ideal gas law, how are the pressure and volume of an ideal gas related?

Accepted Answer

PV is constant

Answer

P is directly proportional to V

Answer

P is inversely proportional to V

Answer

P is proportional to the square of V

Question 41

Which property of a substance measures its resistance to temperature change?

Accepted Answer

Specific heat

Answer

Specific volume

Answer

Thermal conductivity

Answer

Viscosity

Question 42

In a closed system, which process involves only heat transfer?

Accepted Answer

Isothermal

Answer

Adiabatic

Answer

Isochoric

Answer

Isobbaric

Question 43

During a reversible isothermal expansion of a system, the change in entropy is:

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Dependent on the system

Question 44

The critical temperature of a substance is the temperature at which:

Accepted Answer

The liquid and gas phases become indistinguishable

Answer

The vapor pressure equals atmospheric pressure

Answer

A phase change occurs

Answer

The triple point is reached

Question 45

According to the Clausius statement of the Second Law of Thermodynamics, which of the following is true?

Accepted Answer

The entropy of an isolated system remains constant or increases.

Answer

Heat energy can be neither created nor destroyed.

Answer

Energy can be converted from one form to another.

Answer

Heat spontaneously flows from low to high temperatures.

Question 46

A closed system undergoes an isothermal process, where its temperature remains constant. What happens to the system's volume and pressure?

Accepted Answer

Volume and pressure remain constant.

Answer

Volume increases and pressure decreases.

Answer

Volume decreases and pressure increases.

Answer

Volume and pressure change in unpredictable ways.

Question 47

Which characteristic distinguishes a reversible process from an irreversible process?

Accepted Answer

It can be reversed without any change in the system and its surroundings.

Answer

It occurs at a constant temperature.

Answer

It involves no friction or other irreversible effects.

Answer

It is an adiabatic process.

Question 48

In air-conditioning systems, how does relative humidity affect human comfort?

Accepted Answer

Relative humidity influences heat transfer between the body and the air.

Answer

Relative humidity has no impact on comfort.

Answer

High humidity makes people feel cooler.

Answer

Air-conditioning systems only control temperature, not humidity.

Question 49

Entropy is a measure of the:

Accepted Answer

Orderliness or randomness of a system

Answer

Amount of energy in a system

Answer

Temperature of a system

Answer

Pressure of a system

Question 50

Enthalpy is a thermodynamic property that represents the:

Accepted Answer

Heat content of a system at constant pressure

Answer

Total energy of a system

Answer

Entropy of a system

Answer

Specific heat capacity of a system

Question 51

Quality is a dimensionless property used to describe the:

Accepted Answer

Phase composition of a two-phase mixture

Answer

Temperature of a system

Answer

Pressure of a system

Answer

Volume of a system

Question 52

Define entropy in thermodynamics and explain its relationship to reversible processes.

Accepted Answer

Entropy measures system disorder, increasing in irreversible processes.

Answer

Entropy measures system energy, decreasing in reversible processes.

Answer

Entropy measures system work, decreasing in irreversible processes.

Answer

Entropy measures system heat transfer, increasing in reversible processes.

Question 53

Which equation represents the ideal gas law?

Accepted Answer

PV = nRT

Answer

PV = nRT/2

Answer

PV^2 = nRT

Answer

PV = nRT^2

Question 54

Which type of thermodynamic system can exchange both heat and work with the surroundings?

Accepted Answer

Open system

Answer

Closed system

Answer

Isolated system

Answer

Adiabatic system

Question 55

Which process is isentropic?

Accepted Answer

Adiabatic reversible expansion of an ideal gas

Answer

Isothermal compression of a liquid

Answer

Isobaric cooling of a gas

Answer

Isochoric heating of a gas

Question 56

Which property measures the maximum work obtainable from a closed system?

Accepted Answer

Exergy

Answer

Enthalpy

Answer

Specific heat capacity

Answer

Entropy

Question 57

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

Accepted Answer

Energy is conserved during all processes.

Answer

Entropy decreases in isothermal processes.

Answer

Heat flows from cold to hot objects.

Question 58

What is the SI unit of temperature?

Accepted Answer

Kelvin (K)

Answer

Degree Fahrenheit (°F)

Answer

Degree Celsius (°C)

Answer

Rankine (°R)

Question 59

Which of the following is NOT a thermodynamic property?

Accepted Answer

Volume flow rate

Answer

Entropy

Answer

Pressure

Answer

Temperature

Question 60

What is the difference between heat capacity and specific heat capacity?

Accepted Answer

Heat capacity is the amount of heat required to raise the temperature of an object, while specific heat capacity is the amount of heat required to raise the temperature of 1 unit mass of a substance.

Answer

Heat capacity is a measure of the temperature of an object, while specific heat capacity is a measure of the energy content of an object.

Question 61

Which of the following processes is isothermal?

Accepted Answer

A process where the temperature remains constant

Answer

A process where the entropy remains constant

Answer

A process where the volume remains constant

Answer

A process where the pressure remains constant

Question 62

What is the significance of the critical point of a substance?

Accepted Answer

It is the point where the liquid and gas phases become indistinguishable.

Answer

It is the point at which the substance has the lowest density.

Answer

It is the point at which the substance has the highest specific heat capacity.

Question 63

Categorically, which of the following is NOT a thermodynamic property?

Accepted Answer

Time

Answer

Volume

Answer

Pressure

Answer

Temperature

Question 64

Which of the following statements embodies the first law of thermodynamics?

Accepted Answer

Energy cannot be created or destroyed, only transferred or transformed.

Answer

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

Answer

Entropy always increases in an isolated system.