Engineering Thermodynamics: Master the Laws of Energy and Heat Transfer

Question 1

Which of these is NOT a core principle of engineering thermodynamics?

Accepted Answer

Chemical equilibrium

Answer

Energy conservation

Answer

Entropy generation

Question 2

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

Accepted Answer

Joule per Kelvin

Answer

Joule

Answer

Kelvin

Answer

Watt

Question 3

Which thermodynamic property specifically measures the amount of heat energy needed to raise the temperature of a substance by one degree Celsius?

Accepted Answer

Specific heat capacity

Answer

Enthalpy

Answer

Entropy

Answer

Internal energy

Question 4

In conductive heat transfer, how does the surface area of an object impact the rate of heat flow?

Accepted Answer

The heat transfer rate increases proportionally with the surface area.

Answer

The heat transfer rate decreases as the surface area increases.

Answer

The heat transfer rate remains constant regardless of the surface area.

Answer

The heat transfer rate reaches a maximum value as the surface area increases.

Question 5

Precisely state the First Law of Thermodynamics and provide a relatable example showcasing its practical application.

Accepted Answer

The First Law of Thermodynamics asserts that energy can neither be created nor destroyed, only transferred or transformed.

Answer

In accordance with the First Law, heat naturally flows from colder objects to warmer objects.

Answer

The First Law dictates that the total entropy of an isolated system invariably increases over time.

Answer

The First Law implies that heat engines can never achieve 100% efficiency.

Question 6

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

Accepted Answer

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

Answer

The total energy of an isolated system remains constant.

Answer

Entropy must increase in all processes.

Answer

Energy cannot be created or destroyed.

Question 7

A heat engine operates between a high-temperature reservoir at 600 K and a low-temperature reservoir at 300 K. What is the maximum possible efficiency of the engine?

Accepted Answer

33.3%

Answer

50%

Answer

66.7%

Answer

83.3%

Question 8

Which of the following is not a primary mode of heat transfer?

Accepted Answer

Diffusion

Answer

Convection

Answer

Radiation

Answer

Conduction

Question 9

In an adiabatic process, the entropy of a closed system will:

Accepted Answer

Remain constant.

Answer

Increase.

Answer

Decrease.

Answer

Become infinite.

Question 10

Which of the following is not considered a thermodynamic property?

Accepted Answer

Viscosity

Answer

Temperature

Answer

Pressure

Answer

Volume

Question 11

What is the primary function of a heat exchanger in a thermodynamic system?

Accepted Answer

To transfer heat between fluids.

Answer

To regulate temperature.

Answer

To convert heat into work.

Answer

To increase the efficiency of the system.

Question 12

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

Accepted Answer

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

Answer

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

Answer

The entropy of an isolated system increases with time.

Answer

The maximum efficiency of a heat engine is 100%.

Question 13

What is the SI unit for entropy?

Accepted Answer

Joules per Kelvin (J/K)

Answer

Joules (J)

Answer

Kelvin (K)

Answer

Kelvin per Joule (K/J)

Question 14

Which property is NOT characteristic of an ideal gas?

Accepted Answer

Kinetic energy of particles is inversely proportional to temperature.

Answer

Particles have negligible volume.

Answer

Intermolecular forces between particles are negligible.

Answer

Particles travel in straight lines between collisions.

Question 15

The mass flow rate (˙m) of a fluid with density (ρ), velocity (v), and cross-sectional area (A) is given by which equation?

Accepted Answer

˙m = ρvA

Answer

˙m = ρA/v

Answer

˙m = v/ρA

Answer

˙m = A/ρv

Question 16

In a reaction with constant heat capacity (Cp), the enthalpy change (ΔH) is calculated as:

Accepted Answer

ΔH = CpΔT

Answer

ΔH = CpΔT - ΔT

Answer

ΔH = ΔT - CpΔT

Answer

ΔH = CpΔT/ΔT

Question 17

What is the primary function of a condenser in a refrigeration system?

Accepted Answer

To release heat from the refrigerant

Answer

To absorb heat from the refrigerant

Answer

To increase the pressure of the refrigerant

Answer

To decrease the pressure of the refrigerant

Question 18

Which of the following is **not** a characteristic of pure substances?

Accepted Answer

Temperature

Answer

Specific volume

Answer

Specific enthalpy

Answer

Specific heat capacity

Question 19

Which law of thermodynamics states that the entropy of an isolated system can never decrease?

Accepted Answer

Second law

Answer

First law

Answer

Third law

Answer

Zeroth law

Question 20

Which of the following substances has the highest thermal conductivity?

Accepted Answer

Copper

Answer

Water

Answer

Iron

Answer

Aluminum

Question 21

Which statement accurately defines the first law of thermodynamics?

Accepted Answer

Energy can be neither created nor destroyed, but can only be transferred or transformed within a system.

Answer

The sum of the energy within an isolated system can only decrease over time.

Answer

Heat naturally transfers from an object at a lower temperature to an object at a higher temperature.

Answer

The internal energy change of a system equals the heat added to the system minus the work done by the system.

Question 22

What physical quantity measures the degree of disorder or randomness within a system?

Accepted Answer

Entropy

Answer

Energy

Answer

Enthalpy

Answer

Exergy

Question 23

Which system type allows neither mass nor energy to enter or leave?

Accepted Answer

Isolated system

Answer

Open system

Answer

Closed system

Answer

Adiabatic system

Question 24

What is the SI unit for specific heat capacity?

Accepted Answer

Joules per kilogram Kelvin

Answer

Joules per kilogram

Answer

Watts per kilogram

Answer

Watts per kilogram Kelvin

Question 25

Identify the heat transfer mode that does not require a medium for transfer.

Accepted Answer

Radiation

Answer

Conduction

Answer

Convection

Answer

Evaporation

Question 26

Establish the relationship between absolute (Kelvin) temperature and Celsius temperature.

Accepted Answer

T(K) equals T(°C) plus 273.15.

Answer

T(K) equals T(°C) minus 273.15.

Answer

T(K) equals T(°C) divided by 273.15.

Answer

T(K) equals T(°C) multiplied by 273.15.

Question 27

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

Accepted Answer

The law of conservation of energy

Answer

The second law of thermodynamics

Answer

The first law of thermodynamics

Answer

The law of increasing entropy

Question 28

In an adiabatic process, there is:

Accepted Answer

No heat transfer to or from the system

Answer

Heat transfer into the system

Answer

Heat transfer out of the system

Answer

A constant temperature

Question 29

Which of the following processes is considered reversible?

Accepted Answer

An isothermal process

Answer

An adiabatic process

Answer

An isobaric process

Answer

A polytropic process

Question 30

Entropy can be described as:

Accepted Answer

A measure of system disorder or randomness

Answer

A measure of system temperature

Answer

A measure of system energy

Question 31

Which factor does NOT influence heat transfer rate?

Accepted Answer

Gravitational constant

Answer

Surface area

Answer

Temperature difference

Question 32

The primary function of a heat exchanger is:

Accepted Answer

Transferring heat between two fluids

Answer

Generating heat

Answer

Measuring heat

Answer

Storing heat

Question 33

A thermodynamic property is defined as:

Accepted Answer

A characteristic of a system that can be measured without specifying the system's path

Answer

A quantity that changes over time

Answer

A quantity that depends on the system's velocity

Answer

A quantity that is constant for all systems

Question 34

The ideal gas law is applicable to gases that:

Accepted Answer

Behave according to the assumptions of the kinetic molecular theory

Answer

Are at any temperature and pressure

Answer

Are only in liquid or solid states

Question 35

Which of the following best describes the First Law of Thermodynamics?

Accepted Answer

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

Answer

The entropy of an isolated system always increases.

Answer

Heat flows naturally from a colder to a hotter body.

Question 36

Which type of heat transfer occurs due to the movement of molecules or fluids?

Accepted Answer

Convection

Answer

Evaporation

Answer

Conduction

Answer

Radiation

Question 37

What is the change in internal energy of a system if 500 kJ of heat is added to it and the system performs 200 kJ of work on its surroundings?

Accepted Answer

300 kJ

Answer

700 kJ

Answer

-300 kJ

Answer

500 kJ

Question 38

Entropy is a measure of:

Accepted Answer

The randomness or disorder of a system.

Answer

The total energy of a system.

Answer

The temperature of a system.

Answer

The pressure of a system.

Question 39

Which of the following is a path function rather than a state function?

Accepted Answer

Work

Answer

Temperature

Answer

Entropy

Answer

Internal Energy

Question 40

A refrigerator operates by transferring heat from a cold reservoir to a hot reservoir. Which statement about this process is true?

Accepted Answer

Work must be done to accomplish the heat transfer.

Answer

Heat flows spontaneously from cold to hot without any external work.

Answer

The refrigerator violates the Second Law of Thermodynamics.

Question 41

Which of the following components is NOT part of a typical Rankine cycle?

Accepted Answer

Compressor

Answer

Turbine

Answer

Boiler

Answer

Condenser