Energy Analysis of Closed Systems: Interactive Learning Quizzes

Question 1

Which of the following cannot be transferred into or out of a closed system?

Accepted Answer

Mass

Answer

Heat

Answer

Work

Answer

Chemical energy

Question 2

Which of the following statements is **not** a characteristic of an isentropic process in a closed system?

Accepted Answer

Heat transfer occurs

Answer

Entropy remains constant

Answer

Work can be transferred

Answer

Pressure-volume work is path-independent

Question 3

In thermodynamics, which of the following is NOT a common mode of energy transfer into or out of a closed system?

Accepted Answer

Mass transfer

Answer

Heat

Answer

Work

Answer

Radiation

Question 4

In an adiabatic process, what occurs to the internal energy of a closed system?

Accepted Answer

Remains constant

Answer

Increases

Answer

Decreases

Answer

Initially increases, then decreases

Question 5

According to the first law of thermodynamics, which assumption holds true for closed systems?

Accepted Answer

The system's total energy, encompassing both heat and work, remains constant throughout the process.

Answer

Energy transfer occurs solely as heat across the system's boundary.

Answer

The system maintains a constant volume and remains stationary.

Question 6

In a closed system, which statement accurately describes the conservation of mass principle?

Accepted Answer

Total mass within the system remains constant.

Answer

Mass within the system can vary.

Answer

Mass of the fluid and container can differ.

Answer

Mass within the system can be negative.

Question 7

In a reversible adiabatic process involving a closed system, what happens to entropy?

Accepted Answer

It remains constant due to the absence of heat transfer.

Answer

It increases due to heat transfer.

Answer

It decreases due to work transfer.

Question 8

In a closed system undergoing an irreversible process, what happens to the entropy of the system?

Accepted Answer

Increases

Answer

Decreases

Answer

Stays the same

Question 9

In a closed system undergoing a constant-volume process with no work done, what occurs to the system's internal energy?

Accepted Answer

Remains constant

Answer

Increases

Answer

Decreases

Question 10

In a closed system, how can energy be transferred according to the first law of thermodynamics?

Accepted Answer

Through both heat and work

Answer

Only through heat transfer

Answer

Only through work

Answer

Energy cannot be transferred in a closed system

Question 11

In a closed thermodynamic system, what can alter its internal energy (U)?

Accepted Answer

Both heat and work transfer

Answer

Heat transfer alone

Answer

Work transfer alone

Question 12

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

Accepted Answer

Heat transfer and work transfer are equal in magnitude but opposite in sign.

Answer

Heat transfer is non-existent, and work transfer is present.

Answer

Both heat transfer and work transfer are absent.

Answer

Work transfer is absent, and heat transfer is present.

Question 13

In a closed system undergoing a constant-pressure process, heat is transferred into the system while no work is done. How does this process impact the change in the system's internal energy?

Accepted Answer

Change in internal energy equals heat transferred

Answer

No change in internal energy

Answer

Change in internal energy equals work done

Answer

Change in internal energy equals heat transferred minus work done

Question 14

Which of the following is not a recognized mode of energy transfer?

Accepted Answer

Momentum

Answer

Heat

Answer

Work

Answer

Radiation

Question 15

A closed system is defined by:

Accepted Answer

No mass transfer across its boundaries

Answer

No energy transfer across its boundaries

Answer

No momentum transfer across its boundaries

Answer

No radiation transfer across its boundaries

Question 16

The first law of thermodynamics implies that:

Accepted Answer

Energy can neither be created nor destroyed

Answer

Entropy always increases

Answer

Heat flows from cold to hot

Answer

Work is always positive

Question 17

The energy transferred into a system via heat is denoted by:

Accepted Answer

Q

Answer

W

Answer

ΔU

Answer

H

Question 18

A piston-cylinder assembly with a movable piston is an example of a:

Accepted Answer

Closed system

Answer

Open system

Answer

Adiabatic system

Answer

Isothermal system

Question 19

Which process is considered isentropic?

Accepted Answer

Adiabatic reversible expansion

Answer

Isothermal compression

Answer

Adiabatic irreversible expansion

Answer

Isochoric heat addition

Question 20

The efficiency of a heat engine is defined as:

Accepted Answer

Work output divided by heat input

Answer

Heat input divided by work output

Answer

Work input divided by heat rejected

Answer

Heat rejected divided by work output

Question 21

Explain the differences between the conservation of energy and conservation of mass principles in the context of closed systems. Discuss their respective implications for engineering analysis.

Accepted Answer

Both principles apply to closed systems, but the conservation of energy is more fundamental.

Answer

The conservation of mass is more important in closed systems because it ensures that no mass is lost or gained.

Answer

The conservation of energy and conservation of mass are the same principle.

Answer

The conservation of energy does not apply to closed systems because energy can be transferred in and out of the system.

Question 22

A closed system is one that:

Accepted Answer

Does not exchange any mass or energy with its surroundings.

Answer

Exchanges only energy with its surroundings.

Answer

Exchanges only mass with its surroundings.

Answer

Exchanges both energy and mass with its surroundings.

Question 23

Which of the following processes occurs at constant temperature?

Accepted Answer

Isothermal

Answer

Isobaric

Answer

Isochoric

Answer

Adiabatic

Question 24

The efficiency of a heat engine is defined as:

Accepted Answer

The ratio of the work output to the heat input.

Answer

The ratio of the heat output to the work input.

Answer

The ratio of the work output to the change in internal energy of the system.

Answer

The ratio of the change in internal energy of the system to the work input.

Question 25

How does selecting the control volume impact energy analysis in closed systems?

Accepted Answer

It enables the inclusion or exclusion of external energy transfer modes.

Answer

It affects the system's thermodynamic properties.

Answer

It has no effect on the energy analysis.

Answer

It determines the direction of energy transfer within the system.

Question 26

Which property remains constant during an isentropic process?

Accepted Answer

Entropy

Answer

Temperature

Answer

Pressure

Answer

Specific heat

Question 27

A heat engine operates between two reservoirs at temperatures T1 and T2 (T1 > T2). The maximum possible efficiency of the engine is:

Accepted Answer

(T1 - T2) / T1

Answer

(T1 + T2) / T1

Answer

(T2 / T1) - T2

Answer

(T1 - T2) / T2

Question 28

Which of the following is a common assumption made in the analysis of closed systems?

Accepted Answer

There is no mass transfer across the system boundary.

Answer

The system is always in thermal equilibrium.

Answer

The system is always adiabatic.

Answer

The system is always isobaric.

Question 29

Which of the following is NOT a fundamental form of energy transfer in thermodynamics?

Accepted Answer

Mass flow

Answer

Heat

Answer

Work

Answer

Radiation

Question 30

Which of the following systems best fits the description of a closed system in thermodynamics?

Accepted Answer

A sealed container of gas

Answer

A room with an open window

Answer

A flowing river

Answer

A car engine running at constant speed

Question 31

Explain the fundamental difference between heat and work in thermodynamics.

Accepted Answer

Heat is energy transferred due to a temperature difference, while work is energy transferred through a force acting through a distance

Answer

Heat is a form of potential energy, while work is a form of kinetic energy

Answer

Heat is transferred only by conduction, while work is transferred only by radiation

Answer

Heat and work are interchangeable terms in thermodynamics

Question 32

Explain the difference between an exothermic and an endothermic process in terms of heat transfer.

Accepted Answer

Exothermic processes release heat, while endothermic processes absorb heat

Answer

Exothermic processes occur at high temperatures, while endothermic processes occur at low temperatures

Answer

Exothermic processes have positive ΔH, while endothermic processes have negative ΔH

Answer

Exothermic and endothermic processes do not exist

Question 33

A closed system undergoes a process where 400 kJ of heat is added and 150 kJ of work is done on the system. What is the change in internal energy of the system?

Accepted Answer

250 kJ

Answer

400 kJ

Answer

550 kJ

Answer

150 kJ

Question 34

Which of the following processes involves no heat transfer?

Accepted Answer

Adiabatic process

Answer

Isothermal process

Answer

Isobaric process

Answer

Isochoric process

Question 35

In a closed system, how does entropy generation affect the efficiency of energy conversion processes?

Accepted Answer

Entropy generation decreases efficiency by increasing irreversibility.

Answer

Entropy generation increases efficiency by reducing irreversibility.

Answer

Entropy generation has no effect on efficiency.

Question 36

For a Closed System, what is the sign convention for work done on the system?

Accepted Answer

Positive when work is done on the system

Answer

Positive when work is done by the system

Answer

Negative when work is done by the system

Answer

Negative when work is done on the system

Question 37

In a reversible isothermal process involving a gas, which statement holds true?

Accepted Answer

Entropy change is zero.

Answer

Heat transfer is zero.

Answer

Work done is zero.

Answer

Internal energy change is zero.

Question 38

Which concept measures the randomness or disorder within a system?

Accepted Answer

Entropy

Answer

Enthalpy

Answer

Internal Energy

Answer

Gibbs Free Energy

Question 39

In a polytropic process, which quantity remains constant?

Accepted Answer

pV^n

Answer

Pressure

Answer

Temperature

Answer

Volume

Question 40

State the fundamental principle of the first law of thermodynamics.

Accepted Answer

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

Answer

The entropy of a closed system constantly increases.

Answer

Heat naturally flows from colder to hotter objects.

Question 41

Which process is characterized by constant external pressure?

Accepted Answer

A gas expanding in a cylinder with a constant external pressure

Answer

A gas expanding in a vacuum

Answer

A gas compressing in a cylinder with a constant external pressure

Question 42

Which process maintains a constant temperature?

Accepted Answer

A gas expanding in a cylinder while being heated to keep the temperature constant

Answer

A gas expanding in a cylinder with no heat transfer

Answer

A gas compressing in a cylinder while being cooled to keep the temperature constant

Question 43

A closed system undergoes an adiabatic process. Which of the following properties remains constant?

Accepted Answer

Entropy

Answer

Pressure

Answer

Volume

Answer

Temperature

Question 44

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

Accepted Answer

Temperature remains constant.

Answer

Volume changes.

Answer

Pressure remains constant.

Answer

Entropy remains constant.

Question 45

Which of the following processes is considered reversible?

Accepted Answer

A process where the system can return to its initial state without any net change in entropy.

Answer

A process where no energy is lost to the surroundings.

Answer

A process that occurs in a closed system.

Question 46

In a closed system undergoing a process, which quantity is conserved according to the first law of thermodynamics?

Accepted Answer

Total Energy

Answer

Volume

Answer

Mass

Answer

Temperature

Question 47

Which of the following is NOT a recognized mode of energy transfer?

Accepted Answer

Momentum

Answer

Heat

Answer

Work

Answer

Radiation

Question 48

Which of the following is a fundamental postulate of the first law of thermodynamics?

Accepted Answer

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

Answer

All processes are reversible.

Answer

Entropy always decreases in isolated systems.

Answer

Heat always flows from a higher temperature reservoir to a lower temperature reservoir.

Question 49

An adiabatic process is characterized by:

Accepted Answer

No heat transfer across the system boundary.

Answer

Work done on the system.

Answer

Heat transfer out of the system.

Answer

Heat transfer into the system.

Question 50

In a refrigeration system, which of the following statements about the work done is true?

Accepted Answer

Work is done on the system (refrigerator) to remove heat from the cold reservoir.

Answer

No work is required.

Answer

Work is done by the system (refrigerator) to transfer heat to the hot reservoir.

Answer

The work done depends on the temperature difference between the reservoirs.

Question 51

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

Accepted Answer

A sealed container filled with a fixed mass of gas.

Answer

A car engine in operation.

Answer

A flowing river.

Answer

A room with an open doorway.

Question 52

Which of the following processes describes the transfer of energy as work?

Accepted Answer

Stirring a liquid in a sealed container

Answer

Cooling a gas by expanding it through a nozzle

Answer

Heating a room with a radiator

Answer

Charging a battery

Question 53

Which of the following is a defining characteristic of a closed system in thermodynamics?

Accepted Answer

Mass remains constant.

Answer

Volume remains constant.

Answer

Pressure remains constant.

Answer

Temperature remains constant.

Question 54

A closed system undergoes a reversible heat addition process. What happens to the entropy of the system?

Accepted Answer

The entropy of the system increases.

Answer

The entropy of the surroundings increases.

Answer

The entropy of the system decreases.

Answer

The entropy of the system remains constant.

Question 55

What is a limitation of the first law of thermodynamics?

Accepted Answer

It cannot predict the direction of spontaneous processes.

Answer

It cannot be applied to open systems.

Answer

It cannot be used to calculate the efficiency of heat engines.

Question 56

A closed system undergoes a process where its internal energy increases by 100 kJ, and its volume decreases by 0.2 m^3. If the pressure acting on the system is 100 kPa, calculate the work done by the system.

Accepted Answer

-20 kJ

Answer

100 kJ

Answer

20 kJ

Answer

10 kJ

Question 57

A closed system undergoes a process where its entropy decreases. What can be concluded about this process?

Accepted Answer

The process is irreversible.

Answer

The process is reversible.

Answer

The entropy of the surroundings increases.

Answer

The system is in thermal equilibrium with its surroundings.

Question 58

A closed system goes through an adiabatic process. Which statement accurately describes the system during this process?

Accepted Answer

No heat transfer occurs with the surroundings

Answer

Heat is transferred to the system, but no work is done

Answer

Work is done on the system, but no heat transfer occurs

Answer

Both heat transfer and work are done on the system

Question 59

An insulated piston-cylinder setup contains an ideal gas. The gas undergoes a process where its volume decreases by 50%. What is the sign of the work done by the gas?

Accepted Answer

Negative

Answer

Positive

Answer

Zero

Answer

Cannot be determined

Question 60

Which of the following is NOT a form of energy transfer?

Accepted Answer

Mass

Answer

Radiation

Answer

Heat

Answer

Work

Question 61

A closed system is one where:

Accepted Answer

No mass can enter or leave the system.

Answer

Only outward energy transfer is possible.

Answer

Energy can be spontaneously generated within the system.

Answer

Only inward energy transfer is possible.

Question 62

The first law of thermodynamics states that:

Accepted Answer

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

Answer

The total entropy of an isolated system is always constant.

Answer

Heat always flows from a higher temperature to a lower temperature.

Answer

No process is perfectly efficient.

Question 63

Which of the following is a measure of the amount of energy transferred as heat?

Accepted Answer

Joule

Answer

Newton

Answer

Watt

Answer

Kelvin

Question 64

A heat engine is a device that:

Accepted Answer

Converts heat into work.

Answer

Transfers heat without any work.

Answer

Stores heat energy.

Answer

Creates heat energy.