Energy Conservation Principle: Master Thermodynamics with Online Quizzes

Question 1

In an adiabatic process, which property remains constant?

Accepted Answer

Internal energy

Answer

Heat transfer

Answer

Entropy

Answer

Temperature

Question 2

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

Accepted Answer

Evaporation

Answer

Conduction

Answer

Convection

Answer

Radiation

Question 3

Thermal efficiency of a heat engine is calculated as the ratio of:

Accepted Answer

Work output to heat input

Answer

Heat input to work output

Answer

Change in internal energy to work done

Answer

Heat rejected to heat absorbed

Question 4

Entropy of a system measures its:

Accepted Answer

Disorder

Answer

Energy

Answer

Temperature

Answer

Pressure

Question 5

During an isothermal process, the change in entropy is:

Accepted Answer

dS = 0

Answer

dS > 0

Answer

dS < 0

Answer

dS = Q/T

Question 6

Exergy of a system is a measure of its:

Accepted Answer

Available work

Answer

Total energy

Answer

Entropy

Answer

Efficiency

Question 7

'Exergetic efficiency' refers to the:

Accepted Answer

Ratio of actual work output to maximum possible work output

Answer

Ratio of heat input to heat rejected

Answer

Difference between thermal efficiency and actual efficiency

Answer

Entropy generation rate per unit of work output

Question 8

Which of the following correctly describes the First Law of Thermodynamics, also known as the law of energy conservation?

Accepted Answer

Energy can be transferred or converted, but cannot be created or destroyed.

Answer

Energy can be created or destroyed.

Answer

Energy is always lost during a process.

Answer

The total amount of energy in an isolated system varies.

Question 9

In a closed thermodynamic system, which of the following scenarios is possible?

Accepted Answer

Heat and work transfer

Answer

Heat transfer only

Answer

Work transfer only

Answer

No energy transfer

Question 10

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

Accepted Answer

Mass

Answer

Heat

Answer

Work

Answer

Chemical energy

Question 11

Which type of device converts electrical energy into mechanical energy?

Accepted Answer

Motor

Answer

Generator

Answer

Transformer

Answer

Resistor

Question 12

Which of the following thermodynamic cycles represents a closed system?

Accepted Answer

Rankine cycle

Answer

Otto cycle

Answer

Diesel cycle

Answer

Brayton cycle

Question 13

The First Law of Thermodynamics is based on which fundamental assumption?

Accepted Answer

Energy is conserved.

Answer

Temperature is constant.

Answer

Pressure is uniform.

Answer

Entropy increases.

Question 14

According to the Energy Conservation Principle, what happens to the total amount of energy in a thermodynamic process?

Accepted Answer

It remains constant, only changing forms.

Answer

It can be created or destroyed.

Answer

It gradually decreases in quality.

Answer

It is always fully converted without any loss.

Question 15

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

Accepted Answer

Mass transfer

Answer

Heat transfer

Answer

Work

Answer

Radiation

Question 16

According to the First Law of Thermodynamics, the total energy of an isolated system remains constant?

Accepted Answer

True

Answer

False

Answer

Unpredictable

Question 17

The efficiency of a heat engine is defined as:

Accepted Answer

Work output per unit heat input

Answer

Heat input per unit work output

Answer

Difference between heat input and heat output

Answer

Sum of heat input and heat output

Question 18

The Carnot cycle represents:

Accepted Answer

A hypothetical cycle with the highest possible efficiency

Answer

A practical cycle used in all heat engines

Answer

An irreversible cycle with minimum efficiency

Answer

A theoretical cycle that cannot be realized

Question 19

The Zeroth Law of Thermodynamics states that:

Accepted Answer

Two systems in thermal equilibrium with a third system are in thermal equilibrium with each other

Answer

Heat always flows from a colder object to a hotter object

Answer

Energy can neither be created nor destroyed

Answer

The entropy of a perfect crystal at absolute zero is zero

Question 20

An isolated system is characterized by:

Accepted Answer

Not exchanging energy with its surroundings

Answer

Exchanging energy with its surroundings

Answer

Exchanging only heat with its surroundings

Answer

Exchanging only work with its surroundings

Question 21

Which of the following processes is irreversible?

Accepted Answer

Adiabatic compression of a real gas

Answer

Adiabatic expansion of an ideal gas

Answer

Isothermal compression of a liquid

Answer

Isochoric heating of a gas

Question 22

The efficiency of a heat engine is determined by which factor?

Accepted Answer

The ratio of work done to heat absorbed

Answer

The temperature difference between the hot and cold reservoirs

Answer

The amount of work done by the engine

Answer

The amount of heat rejected by the engine

Question 23

Which of the following characterizes an isothermal process?

Accepted Answer

Constant temperature

Answer

Constant pressure

Answer

Constant volume

Answer

Constant entropy

Question 24

The enthalpy of a system is defined as:

Accepted Answer

The internal energy of the system plus the product of pressure and volume

Answer

The internal energy of the system minus the product of pressure and volume

Answer

The heat capacity of the system multiplied by the temperature

Answer

The entropy of the system divided by the temperature

Question 25

Which of the following is a direct implication of the Second Law of Thermodynamics?

Accepted Answer

Entropy increases in irreversible processes

Answer

Heat spontaneously flows from cold to hot objects

Answer

Real processes are always reversible

Answer

The universe is constantly expanding

Question 26

To optimize energy systems, which factor is essential to consider?

Accepted Answer

Minimizing energy loss

Answer

Increasing energy use

Answer

Disregarding energy transfer processes

Question 27

In a closed thermodynamic system, energy can be exchanged with the surroundings. Which of the following describes the nature of this energy exchange?

Accepted Answer

Energy can be transferred into or out of the system.

Answer

Energy can be transferred only into the system.

Answer

Energy can be transferred only out of the system.

Answer

No energy can be transferred into or out of the system.

Question 28

The First Law of Thermodynamics states that the change in internal energy of a system is equal to:

Accepted Answer

Heat added to the system minus work done by the system

Answer

Heat removed from the system minus work done on the system

Answer

Work done by the system minus heat added to the system

Answer

Work done on the system minus heat removed from the system

Question 29

An adiabatic process is characterized by:

Accepted Answer

No heat transfer between the system and the surroundings

Answer

Heat transfer into the system at constant volume

Answer

Heat transfer out of the system at constant pressure

Answer

Heat transfer into the system at constant temperature

Question 30

During an isothermal reversible process, the change in entropy of the system is:

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Indeterminate

Question 31

Which of the following is NOT a consequence of the Second Law of Thermodynamics?

Accepted Answer

Energy can be created or destroyed.

Answer

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

Answer

The entropy of an isolated system always increases over time.

Answer

No work can be converted into heat with 100% efficiency.

Question 32

The efficiency of a heat engine operating between two fixed temperatures is:

Accepted Answer

Equal to the ratio of the absolute temperatures of the two reservoirs.

Answer

Equal to the difference between the absolute temperatures of the two reservoirs.

Answer

Equal to the sum of the absolute temperatures of the two reservoirs.

Answer

Not related to the temperatures of the reservoirs.

Question 33

The enthalpy change of a reaction is:

Accepted Answer

The heat absorbed or released at constant pressure.

Answer

The heat absorbed or released at constant volume.

Answer

The change in internal energy of the system.

Answer

The change in entropy of the system.

Question 34

Which of the following is a thermodynamic property that does not depend on the path taken?

Accepted Answer

Temperature

Answer

Volume

Answer

Work

Answer

Heat

Question 35

For an ideal gas, the heat capacity ratio is:

Accepted Answer

Equal to the specific heat ratio.

Answer

Greater than the specific heat ratio.

Answer

Less than the specific heat ratio.

Answer

Indeterminate

Question 36

What is the relationship between entropy and disorder in a thermodynamic system?

Accepted Answer

Entropy measures the level of randomness or disorder in a system.

Answer

In an isolated system, entropy remains constant.

Answer

Entropy is always positive for a closed system.

Answer

Entropy is unaffected by heat transfer.

Question 37

According to the First Law of Thermodynamics, what happens to the total energy of an isolated system?

Accepted Answer

It remains constant.

Answer

It can be created or destroyed.

Answer

It is converted into heat and work.

Question 38

Consider an ideal gas undergoing a process described by the equation PV^n = constant. Determine the relationship between the work done by the gas and the change in volume.

Accepted Answer

The work done by the gas is proportional to V^(1-n).

Answer

The work done on the gas is proportional to V^(n-1).

Answer

The heat transfer into the gas is proportional to V^(n-1).

Question 39

Identify the incorrect statement regarding the energy conservation principle.

Accepted Answer

Energy can be created or destroyed.

Answer

The total energy of an isolated system remains constant.

Answer

Energy can be transferred from one form to another.

Answer

Energy has different qualities.

Question 40

Consider a closed system undergoing a cyclic process that returns it to its initial state. What can be said about the net work done by the system?

Accepted Answer

The net work done is zero.

Answer

The net work done is equivalent to the work done in the first half of the cycle.

Answer

The net work done is equivalent to the work done in the second half of the cycle.