Master Thermodynamics: Enhance Your Engineering Expertise

Question 1

Which statement does NOT describe the second law of thermodynamics?

Accepted Answer

Heat flows spontaneously from colder to hotter bodies.

Answer

The entropy of an isolated system increases over time.

Answer

Heat engines cannot operate with 100% efficiency.

Answer

Perpetual motion machines are impossible.

Question 2

According to the first law of thermodynamics, what happens to energy?

Accepted Answer

It can only be transferred or transformed.

Answer

It can be created and destroyed at will.

Answer

It always flows from a colder object to a warmer object.

Answer

The total entropy of an isolated system always decreases over time.

Question 3

According to the second law of thermodynamics, what happens to the entropy of an isolated system over time?

Accepted Answer

Increases

Answer

Decreases

Answer

Stays the same

Answer

Can increase or decrease

Question 4

According to the second law of thermodynamics, what happens to the total entropy of an isolated system?

Accepted Answer

It increases or remains constant.

Answer

It decreases.

Answer

It becomes negative.

Answer

It is conserved.

Question 5

Under the second law of thermodynamics, what happens to the entropy of a closed system?

Accepted Answer

Always increases

Answer

Stays the same

Answer

Decreases to zero

Answer

Proportional to temperature

Question 6

Which statement accurately reflects the Clausius statement of the second law of thermodynamics?

Accepted Answer

Entropy always increases in an isolated system.

Answer

Entropy decreases over time in all systems.

Answer

The efficiency of a heat engine is always 100%.

Answer

Heat can spontaneously flow from a cold reservoir to a hot reservoir.

Question 7

According to the first law of thermodynamics, which physical quantity remains constant?

Accepted Answer

Energy

Answer

Mass

Answer

Momentum

Answer

Charge

Question 8

Which concept is not a fundamental principle of thermodynamics?

Accepted Answer

Momentum

Answer

Energy

Answer

Entropy

Answer

Heat

Question 9

According to the first law of thermodynamics, which action would violate the principle of energy conservation in an isolated system?

Accepted Answer

Creating something out of nothing

Answer

Burning a fuel

Answer

Heating a room with a heater

Answer

Generating electricity from a solar panel

Question 10

In a closed system undergoing a cyclic process, what is true about the net heat transfer?

Accepted Answer

It is zero.

Answer

It is necessarily zero.

Answer

It increases.

Answer

It decreases.

Question 11

According to the Second Law of Thermodynamics, in which direction does heat flow occur?

Accepted Answer

From higher temperature objects to lower temperature objects

Answer

From lower temperature objects to higher temperature objects

Answer

From isolated systems to non-isolated systems

Answer

From less efficient heat engines to more efficient heat engines

Question 12

In a closed system undergoing a constant-volume process, what happens to its internal energy when heat is transferred into it?

Accepted Answer

Increases

Answer

Decreases

Answer

Remains the same

Question 13

In an ideal Otto cycle, what is the sequence of processes?

Accepted Answer

Isentropic compression, Isochoric heat addition, Isentropic expansion, Isochoric heat rejection

Answer

Isobaric expansion, Isochoric compression, Isobaric compression, Isochoric expansion

Answer

Isochoric heat rejection, Isentropic expansion, Isochoric heat addition, Isentropic compression

Question 14

In an isolated system, what occurs to the total energy, according to the first law of thermodynamics?

Accepted Answer

It stays the same.

Answer

It can be created or destroyed.

Answer

It gradually diminishes.

Question 15

What is the correct definition of entropy?

Accepted Answer

A measure of the disorder of a system

Answer

A quantity that always decreases in an isolated system

Answer

A conserved quantity

Answer

Directly proportional to temperature

Question 16

In the Diesel cycle, which process involves heat rejection while maintaining a constant volume?

Accepted Answer

Constant-volume heat rejection

Answer

Isentropic compression

Answer

Isentropic expansion

Answer

Constant-volume heat addition

Question 17

Which process in a Diesel cycle involves heat rejection at constant pressure?

Accepted Answer

Constant pressure heat rejection

Answer

Isentropic compression

Answer

Adiabatic expansion

Answer

Isochoric heat addition

Question 18

In an isothermal and reversible closed system, what happens to the internal energy during the process?

Accepted Answer

Remains constant

Answer

Increases

Answer

Decreases

Answer

Cannot be determined without additional information

Question 19

In a Rankine cycle, where does the heat addition process take place?

Accepted Answer

Boiler

Answer

Condenser

Answer

Turbine

Answer

Pump

Question 20

In a closed thermodynamic system, the first law of thermodynamics states that energy can only be transferred in two forms. Which energy transfer is associated with changes in the system's volume?

Accepted Answer

Work transfer

Answer

Heat transfer

Answer

Mass transfer

Answer

Chemical energy transfer

Question 21

What is the primary significance of the second law of thermodynamics?

Accepted Answer

It establishes a fundamental directionality in natural processes, such as the flow of heat and the degradation of energy.

Answer

It provides a mathematical framework for calculating the efficiency of heat engines.

Answer

It allows scientists to predict the behavior of systems at the atomic and molecular level.

Answer

It explains how energy can be converted from one form to another without losing its usefulness.

Question 22

In a Diesel cycle, which process involves heat transfer from the air-fuel mixture to the surrounding environment?

Accepted Answer

Constant volume heat rejection

Answer

Intake stroke

Answer

Compression stroke

Answer

Power stroke

Question 23

According to the second law of thermodynamics, what happens to the total entropy of an isolated system over time?

Accepted Answer

Increases or remains constant

Answer

Decreases

Answer

Remains constant

Answer

Increases

Question 24

In a Brayton cycle, which process entails adding heat to the working fluid while maintaining constant pressure?

Accepted Answer

Constant pressure heat addition

Answer

Isentropic compression

Answer

Constant volume heat addition

Answer

Isentropic expansion

Question 25

In a closed system, which statement about entropy is correct?

Accepted Answer

Entropy measures the disorder of a system.

Answer

Entropy always decreases.

Answer

Entropy can be created or destroyed.

Answer

Entropy is always zero for an isolated system.

Question 26

Which process in the Otto cycle involves compressing the air-fuel mixture?

Accepted Answer

Adiabatic compression

Answer

Isobaric compression

Answer

Isothermal compression

Answer

Isochoric compression

Question 27

Define exergy and explain its importance in thermodynamic analysis.

Accepted Answer

Exergy is the maximum useful work that can be extracted from a system during a reversible process to a reference environment.

Answer

Exergy is the energy lost due to irreversible processes like friction.

Answer

Exergy is equivalent to enthalpy and can be calculated using the same formulas.

Answer

Exergy is an irrelevant concept in thermodynamics and can be disregarded in practical applications.

Question 28

How does the second law of thermodynamics impact environmental sustainability and energy policy?

Accepted Answer

It limits the efficiency of energy conversion, making it impossible to eliminate waste heat.

Answer

It supports the development of perpetual motion machines.

Answer

It has no practical implications for these areas.

Answer

It suggests that the universe is becoming increasingly chaotic.

Question 29

Explain the various modes of heat transfer and discuss their relative significance in different engineering applications.

Accepted Answer

The relevance of specific heat transfer mechanisms varies depending on the application.

Answer

Conduction, convection, and radiation are the exclusive modes of heat transfer.

Answer

Radiation dominates as the primary mode of heat transfer in most engineering applications.

Question 30

According to the statistical definition of entropy, which of the following factors does **NOT** contribute to the entropy of a system?

Accepted Answer

Temperature

Answer

Number of possible microstates

Answer

Molecular disorder

Answer

Volume

Question 31

A closed system undergoes a process where its internal energy increases while its volume decreases. Which of the following best describes this process?

Accepted Answer

Irreversible adiabatic process

Answer

Reversible isothermal process

Answer

Reversible adiabatic process

Answer

Irreversible isothermal process

Question 32

Explain the significance of the second law of thermodynamics in energy conversion and utilization. How does it affect the efficiency and performance of energy systems?

Accepted Answer

The second law of thermodynamics helps determine the maximum possible efficiency of energy conversion systems and guides strategies to improve their performance.

Answer

The second law of thermodynamics does not limit the efficiency of energy conversion.

Answer

All energy conversion processes have an efficiency of 100% according to the second law of thermodynamics.

Answer

The second law of thermodynamics has no practical relevance in designing and operating energy systems.

Question 33

Which of the following accurately states the first law of thermodynamics?

Accepted Answer

Energy cannot be created or destroyed but can be transformed.

Answer

Entropy always increases in a closed system.

Answer

Heat always flows from a colder to a hotter object.

Answer

Engines can convert 100% of heat input into work.

Question 34

A system with fixed boundaries and no mass exchange with the surroundings is called a:

Accepted Answer

Closed system.

Answer

Open system.

Answer

Isolated system.

Answer

Thermodynamic system.

Question 35

Following an irreversible process, the entropy of an isolated system will:

Accepted Answer

Increase.

Answer

Remain unchanged.

Answer

Decrease.

Answer

Cannot be determined.

Question 36

What is the theoretical maximum efficiency of a heat engine operating between two reservoirs at temperatures T1 and T2?

Accepted Answer

1 - (T2 / T1)

Answer

T1 / (T1 + T2)

Answer

(T1 - T2) / T1

Answer

Cannot be determined without additional information.

Question 37

Which of the following is NOT a state property?

Accepted Answer

Work.

Answer

Temperature.

Answer

Pressure.

Answer

Volume.

Question 38

What is enthalpy defined as?

Accepted Answer

Internal energy plus the product of pressure and volume.

Answer

Internal energy plus entropy.

Answer

Internal energy minus the product of pressure and volume.

Answer

Internal energy minus entropy.

Question 39

In a refrigeration system, what is the primary function of a condenser?

Accepted Answer

To release heat from the refrigerant.

Answer

To absorb heat from the refrigerant.

Answer

To convert the refrigerant from liquid to gas.

Answer

To convert the refrigerant from gas to liquid.

Question 40

Which of the following accurately states the first law of thermodynamics?

Accepted Answer

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

Answer

Energy is always lost in any process.

Answer

Heat and work are equivalent forms of energy.

Answer

Entropy is always increasing.

Question 41

For a Carnot engine operating between temperatures T1 and T2, what is its theoretical maximum efficiency?

Accepted Answer

(T1 - T2)/T1

Answer

0%

Answer

50%

Answer

100%

Question 42

What is the definition of Gibbs free energy for a system?

Accepted Answer

The maximum useful work that can be extracted from the system

Answer

The minimum energy required to create the system

Answer

The change in entropy of the system

Answer

The heat capacity of the system

Question 43

Explain the connection between entropy and disorder. Provide examples to demonstrate how a rise in entropy can result in increased disorder within a system.

Accepted Answer

Entropy measures disorder; an increase signifies more disorder.

Answer

Entropy measures energy; higher entropy means more energy.

Answer

Entropy measures heat; higher entropy means higher temperatures.

Answer

Entropy measures time; higher entropy means longer durations.

Question 44

How does the second law of thermodynamics impact the design and operation of refrigeration and air conditioning systems?

Accepted Answer

It necessitates efficient system design.

Answer

It prohibits refrigerants with high global warming potential.

Answer

It enables systems to cool without energy consumption.

Question 45

In a closed system undergoing an isothermal process, what occurs to the system's entropy?

Accepted Answer

Remains constant

Answer

Increases

Answer

Decreases

Answer

Increases if the process is irreversible

Question 46

Identify the property that is NOT characteristic of a thermodynamic system:

Accepted Answer

Colour

Answer

Temperature

Answer

Pressure

Answer

Entropy

Question 47

Which process exhibits isentropic characteristics?

Accepted Answer

Reversible adiabatic process

Answer

Irreversible adiabatic process

Answer

Isothermal process

Answer

Isobarik process

Question 48

What is the primary significance of Gibbs free energy in a system?

Accepted Answer

Maximum possible work output

Answer

Minimum work input required

Answer

Entropy change

Answer

Enthalpy change

Question 49

Which definition accurately describes specific heat capacity?

Accepted Answer

Heat required to raise the temperature of 1 kg of a substance by 1 K

Answer

Heat required to raise the temperature of 1 mole of a substance by 1 K

Answer

Heat required to raise the temperature of 1 g of a substance by 1 °C

Answer

Heat required to raise the temperature of a substance by 1 K

Question 50

Which process exemplifies a reversible process?

Accepted Answer

Isothermal liquid vaporisation

Answer

Gas expansion into a vacuum

Answer

Adiabatic gas compression

Answer

Heat transfer with a finite temperature difference

Question 51

What quantity does entropy represent in a system?

Accepted Answer

Disorder

Answer

Energy

Answer

Volume

Answer

Temperature

Question 52

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

Accepted Answer

Velocity

Answer

Temperature

Answer

Pressure

Answer

Volume

Question 53

Distinguish between heat and internal energy.

Accepted Answer

Heat is a form of energy that can be transferred between systems, while internal energy represents the energy within a system.

Answer

Heat is the energy associated with the motion of molecules, while internal energy encompasses all forms of energy within a system.

Answer

There is no distinction between heat and internal energy.

Answer

Heat is a measure of temperature, while internal energy is a measure of the total energy of a system.

Question 54

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

Accepted Answer

Partially open system

Answer

Open system

Answer

Closed system

Answer

Isolated system

Question 55

What is the significance of Gibbs free energy in chemical reactions?

Accepted Answer

It determines the spontaneity of a reaction under constant temperature and pressure.

Answer

It measures the maximum amount of work that can be obtained from a reaction.

Answer

It indicates the equilibrium state of a reaction.

Answer

It is a measure of the entropy change of a reaction.

Question 56

What is the relationship between entropy and disorder?

Accepted Answer

Entropy is a measure of disorder.

Answer

Entropy always increases in closed systems.

Answer

Entropy is only defined for ideal gases.

Answer

Entropy is a measure of heat transfer.

Question 57

Explain the contrasting implications of the first and second laws of thermodynamics on energy conservation and system behavior.

Accepted Answer

First Law: Energy is conserved in closed systems; Second Law: Systems tend towards disorder.

Answer

First Law: Energy can be created or destroyed; Second Law: Entropy always increases.

Answer

First Law: Heat can flow spontaneously from a colder to a hotter body; Second Law: No process is 100% efficient.

Answer

First Law: Entropy decreases with time; Second Law: Heat engines can operate without a cold reservoir.

Question 58

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

Accepted Answer

It remains constant.

Answer

It is created and destroyed.

Answer

It increases.

Answer

It decreases.

Question 59

What is the relationship between the entropy of an ideal gas and its volume?

Accepted Answer

Entropy is directly proportional to volume.

Answer

Entropy is inversely proportional to volume.

Answer

Entropy is independent of volume.

Answer

Entropy is proportional to the square of volume.

Question 60

What is the definition of Gibbs free energy?

Accepted Answer

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

Answer

The minimum amount of work required to perform a process at constant temperature and volume.

Answer

The maximum amount of heat that can be transferred from a system at constant temperature and volume.

Answer

The minimum amount of heat required to perform a process at constant temperature and pressure.

Question 61

Which of the following devices is a heat engine?

Accepted Answer

Car engine

Answer

Refrigerator

Answer

Air conditioner

Answer

Solar cell

Question 62

Which thermodynamic property measures the level of disorder or randomness in a system?

Accepted Answer

Entropy

Answer

Enthalpy

Answer

Gibbs free energy

Question 63

How do the principles of thermodynamics guide the design and operation of renewable energy systems like solar photovoltaic panels?

Accepted Answer

The first law of thermodynamics ensures that the total energy entering a system equals the total energy leaving it.

Accepted Answer

The second law of thermodynamics implies that the entropy of a closed system always increases over time.

Answer

The third law of thermodynamics states that the entropy of a perfect crystal at absolute zero is zero.

Answer

The principles of thermodynamics do not apply to renewable energy systems because these systems are based on non-renewable energy sources.

Question 64

How does entropy limit the efficiency of refrigeration and air conditioning systems?

Accepted Answer

Entropy production limits the maximum achievable system efficiency.

Answer

Lower entropy enhances system efficiency.

Answer

Higher entropy enhances system efficiency.