500+ Engineering Thermodynamics Solved MCQs

Engineering thermodynamics is a branch of engineering that deals with the study of energy, heat, and their relationship to work and the transfer of energy from one place to another.

It is a fundamental subject that forms the basis of many other branches of engineering, including mechanical, chemical, and electrical engineering. The principles of thermodynamics are used to design engines, power plants, refrigeration systems, and a wide variety of other devices and systems that are essential to modern society. Some of the key concepts in engineering thermodynamics include the laws of thermodynamics, entropy, and the concept of equilibrium.

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .

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251.	All actual heat transfer processes are
A.	irreversible
B.	take place through a finite temperature difference
C.	both of the mentioned
D.	none of the mentioned
Answer» C. both of the mentioned

252.	Free expansion is irreversible.
A.	true
B.	false
Answer» A. true

253.	Which of the following can be a cause of irreversibility?
A.	friction, viscosity
B.	inelasticity
C.	electrical resistance, magnetic hysteresis
D.	all of the mentioned
Answer» D. all of the mentioned

254.	The continual motion of a movable device in the complete absence of friction is known as
A.	pmm2
B.	pmm3
C.	pmm1
D.	pmm0
Answer» B. pmm3

255.	The friction present in moving devices makes a process reversible.
A.	true
B.	false
Answer» B. false

256.	Which of the following is irreversible?
A.	stirring work
B.	friction work in moving devices
C.	current flowing through a wire
D.	all of the mentioned
Answer» D. all of the mentioned

257.	A process will be reversible if it has
A.	no dissipative effects
B.	dissipative effects
C.	depends on the given conditions
D.	none of the mentioned
Answer» A. no dissipative effects

258.	Irreversibility can be distinguished in how many types?
A.	0
B.	1
C.	2
D.	3
Answer» C. 2

259.	Internal irreversibility is caused by
A.	internal dissipative effects
B.	friction, turbulence
C.	electrical resistance, magnetic hysteresis
D.	all of the mentioned
Answer» D. all of the mentioned

260.	The external irreversibility occurs at the system boundary.
A.	true
B.	false
Answer» A. true

261.	Which of the following is true?
A.	mechanical irreversibility is due to finite pressure gradient
B.	thermal irreversibility is due to finite temperature gradient
C.	chemical irreversibility is due to finite concentration gradient
D.	all of the mentioned
Answer» D. all of the mentioned

262.	The magnitude of mechanical work is the
A.	product of the force and distance travelled perpendicular to the force
B.	product of the force and distance travelled parallel to the force
C.	sum of the force and distance travelled perpendicular to the force
D.	sum of the force and distance travelled parallel to the force
Answer» B. product of the force and distance travelled parallel to the force

263.	Work done by a system is taken to be
A.	positive
B.	negative
C.	zero
D.	varies according to situation
Answer» A. positive

264.	Work done on a system is taken to be
A.	positive
B.	negative
C.	zero
D.	varies according to situation
Answer» B. negative

265.	Work is a
A.	point function
B.	path function
C.	depends on the state
D.	none of the mentioned
Answer» B. path function

266.	Thermodynamic properties are
A.	point function
B.	path function
C.	depends on the state
D.	none of the mentioned
Answer» A. point function

267.	In the equation dV=(1/p)dW, (1/p) is known as
A.	volume factor
B.	pressure factor
C.	differential factor
D.	integration factor
Answer» D. integration factor

268.	Cyclic integral of a property is always
A.	zero
B.	one
C.	infinite value
D.	none of the mentioned
Answer» A. zero

269.	Constant pressure process is also known as
A.	isopiestic process
B.	isobaric process
C.	all of the mentioned
D.	none of the mentioned
Answer» C. all of the mentioned

270.	Work done in a quasi-static process
A.	depends on the path followed
B.	independent of the path followed
C.	depends only on the initial and final states
D.	none of the mentioned
Answer» A. depends on the path followed

271.	A saturation state is a state from which a change of phase may occur
A.	without a change of pressure or temperature
B.	with a change of pressure or temperature
C.	both of the mentioned
D.	none of the mentioned
Answer» A. without a change of pressure or temperature

272.	In which of the following state does water exist?
A.	saturated solid state
B.	saturated liquid state
C.	saturated vapour state
D.	all of the mentioned
Answer» D. all of the mentioned

273.	5 P-V DIAGRAM.
A.	saturated solid line
B.	saturated liquid lines
C.	saturated vapour line
D.	all of the mentioned
Answer» D. all of the mentioned

274.	The triple point is a line on the p-V diagram, where all the three phases, solid, liquid and gas exist.
A.	true
B.	false
Answer» A. true

275.	At a pressure below the triple point line,
A.	the substance cannot exist in the liquid phase
B.	the substance when heated transforms from solid to vapour
C.	both of the mentioned
D.	none of the mentioned
Answer» C. both of the mentioned

500+ Engineering Thermodynamics Solved MCQs

All actual heat transfer processes are

Free expansion is irreversible.

Which of the following can be a cause of irreversibility?

The continual motion of a movable device in the complete absence of friction is known as

The friction present in moving devices makes a process reversible.

Which of the following is irreversible?

A process will be reversible if it has

Irreversibility can be distinguished in how many types?

Internal irreversibility is caused by

The external irreversibility occurs at the system boundary.

Which of the following is true?

The magnitude of mechanical work is the

Work done by a system is taken to be

Work done on a system is taken to be

Work is a

Thermodynamic properties are

In the equation dV=(1/p)dW, (1/p) is known as

Cyclic integral of a property is always

Constant pressure process is also known as

Work done in a quasi-static process

A saturation state is a state from which a change of phase may occur

In which of the following state does water exist?

5 P-V DIAGRAM.

The triple point is a line on the p-V diagram, where all the three phases, solid, liquid and gas exist.

At a pressure below the triple point line,

Which of the following statement is true?

The greater the temperature, the is the vapour pressure.

Phase change occurs at

Which of the following statement is true?

At absolute zero, an isotherm and an adiabatic are identical.

When the heat transferred isothermally

First law of thermodynamics deals with

During a fluid flow, the temperature is developed due to

The equation for the average kinetic energy is

Entropy occurs due to

What is the equation of entropy?

SI unit of enthalpy is

Which among this is not an exothermic reaction?

What reaction takes place during photosynthesis?

The first law of thermodynamics doesn’t tell us whether a thermodynamic process is feasible or not.

According to Joule’s experiments,

Which of the following is true?

Boiler, turbine, condenser and pump together constitute a heat engine.

In a heat engine cycle, which of the following process occurs?

A thermal energy reservoir is a large body of

Processes inside a thermal energy reservoir are quasi-static.

Carnot cycle is a reversible cycle.

Which if the following statements are true for a mechanical energy reservoir(MER)?

The correct sequence of the processes taking place in a carnot cycle is

Example of reversed heat engine is

276.	Which of the following statement is true?
A.	to the left of saturated solid line is the solid region
B.	between saturated solid line and saturated liquid line with respect to solidification there exists the solid-liquid mixture region
C.	between two saturated liquid lines is the compressed liquid region
D.	all of the mentioned
Answer» D. all of the mentioned

277.	The greater the temperature, the is the vapour pressure.
A.	lower
B.	higher
C.	depends on the substance
D.	none of the mentioned
Answer» B. higher

278.	Phase change occurs at
A.	constant pressure
B.	constant temperature
C.	constant pressure and temperature
D.	none of the mentioned
Answer» C. constant pressure and temperature

279.	Which of the following statement is true?
A.	saturation temperature is a function of pressure
B.	saturation pressure is a function of temperature
C.	both of the mentioned
D.	none of the mentioned
Answer» C. both of the mentioned

280.	At absolute zero, an isotherm and an adiabatic are identical.
A.	true
B.	false
Answer» A. true

281.	When the heat transferred isothermally
A.	doesnot, can, without
B.	exists, cannot, without
C.	exists, can, with
D.	none of the mentioned
Answer» B. exists, cannot, without

282.	First law of thermodynamics deals with
A.	conservation of mass
B.	conservation of momentum
C.	conservation of energy
D.	conservation of pressure
Answer» C. conservation of energy

283.	During a fluid flow, the temperature is developed due to
A.	increase in density
B.	change in pressure
C.	translational kinetic energy
D.	fluid level
Answer» C. translational kinetic energy

284.	The equation for the average kinetic energy is
A.	0.5 kt
B.	1.5 kt
C.	2.5 kt
D.	3.5 kt
Answer» B. 1.5 kt

285.	Entropy occurs due to
A.	change in macroscopic variables
B.	volumetric changes only
C.	mass changes only
D.	temperature only
Answer» A. change in macroscopic variables