The work ratio of a gas turbine plant is given by

(Net work output)/(Heat supplied)

(Net work output)/(Work-done by the turbine)

(Net work output)/(Heat supplied)

(Actual temperature drop)/(Isentropic temperature drop)

(Isentropic increase in temperature)/(Actual increase in temperature)

Which of the following is the correct statement?

All engines are designed as reversible in order to obtain maximum efficiency.

All the reversible engines have the same efficiency.

All the reversible and irreversible engines have the same efficiency.

Irreversible engines have maximum efficiency.

All engines are designed as reversible in order to obtain maximum efficiency.

When a gas is heated at constant pressure

neither temperature not volume will increase

both temperature and volume will increase

neither temperature not volume will increase

Which of the following statement is correct according to Clausis statement of second law off thermodynamics?

It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle.

It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature.

It is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature, without the aid of an external source.

It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle.

Carnot cycle consists of

two constant pressure and two isentropic processes

two constant volume and two isentropic processes

two isothermal and two isentropic processes

two constant pressure and two isentropic processes

one constant volume, one constant pressure and two isentropic processes

For the constant pressure and heat input, the air standard efficiency of gas power cycle is in the order

Otto cycle, Diesel cycle, Dual cycle

Dual cycle, Diesel cycle, Otto cycle

Otto cycle, Diesel cycle, Dual cycle

Dual cycle, Otto cycle, Diesel cycle

Diesel cycle, Otto cycle, Dual cycle

When the gas is cooled at constant pressure,

its temperature increases but volume decreases

its volume increases but temperature decreases

both temperature and volume increases

both temperature and volume decreases

When the gas is heated at constant pressure, the heat supplied

increases the internal energy of the gas

increases the temperature of the gas

does some external work during expansion

425 + Mcqs in Thermodynamics in Graduate Aptitude Test (GATE) Page 5 McqOptions

201.	In closed cycle gas turbine, the air is compressed
A.	isothermally
B.	isentropically
C.	polytropically
D.	none of these
Answer» C. polytropically

Discussion

202.	The __________ is obtained when carbonisation of coal is carried out at 500° to 700° C.
A.	soft coke
B.	hard coke
C.	pulverised coal
D.	bituminous coal
Answer» B. hard coke

Discussion

203.	In S. I. units, the value of the universal gas constant is
A.	8.314 J/kg mole-K
B.	83.14 J/kgmole-K
C.	831.4 J/kgmole-K
D.	8314 J/kgmole-K
Answer» E.

Discussion

204.	The heat flows from a cold body to a hot body with the aid of an external source. This statement is given by
A.	Kelvin
B.	Joule
C.	Clausis
D.	Gay-Lussac
Answer» D. Gay-Lussac

Discussion

205.	The lower calorific value of fuel may be obtained by adding the heat of steam formed during combustion to the higher calorific value.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

206.	The work ratio of a gas turbine plant is given by
A.	(Net work output)/(Work-done by the turbine)
B.	(Net work output)/(Heat supplied)
C.	(Actual temperature drop)/(Isentropic temperature drop)
D.	(Isentropic increase in temperature)/(Actual increase in temperature)
Answer» B. (Net work output)/(Heat supplied)

Discussion

207.	The efficiency of the dual combustion cycle for the same compression ratio, is __________ Diesel cycle.
A.	greater than
B.	less than
C.	equal to
D.	None of these
Answer» B. less than

Discussion

208.	When a perfect gas is expanded through an aperture of minute dimensions, the process is known as
A.	isothermal process
B.	adiabatic process
C.	free expansion process
D.	throttling process
Answer» E.

Discussion

209.	The gas in cooling chamber of a closed cycle gas turbine is cooled at
A.	constant volume
B.	constant temperature
C.	constant pressure
D.	none of these
Answer» D. none of these

Discussion

210.	The state of a substance whose evaporation from its liquid state is partial, is known as steam.
A.	Agree
B.	Disagree
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

211.	The unit of energy is S. I. units is
A.	Joule (J)
B.	Joule metre (Jm)
C.	Watt(W)
D.	Joule/metre (J/m)
Answer» B. Joule metre (Jm)

Discussion

212.	A path 1-2-3 is given. A system absorbs 100 kJ as heat and does 60 kJ of work while along the path 1-4-3, it does 20 kJ of work. The heat absorbed during the cycle 1-4-3 is
A.	-140 kJ
B.	-80 kJ
C.	-40 kJ
D.	+60 kJ
Answer» E.

Discussion

213.	Both the Ericsson and Joule's cycle have two constant pressure processes.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

214.	Which of the following is the correct statement?
A.	All the reversible engines have the same efficiency.
B.	All the reversible and irreversible engines have the same efficiency.
C.	Irreversible engines have maximum efficiency.
D.	All engines are designed as reversible in order to obtain maximum efficiency.
Answer» D. All engines are designed as reversible in order to obtain maximum efficiency.

Discussion

215.	According to Gay-Lussac law, the absolute pressure of a given mass of a perfect gas varies __________ as its absolute temperature, when the volume remains constant.
A.	directly
B.	indirectly
C.	Can't say
D.	None of these
Answer» B. indirectly

Discussion

216.	Briquetted coal is produced from the finely ground coal by moulding under pressure with or without a binding material.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

217.	A closed cycle gas turbine works on Joule's cycle.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

218.	Coke oven gas is obtained by burning coke in an oven.
A.	Agree
B.	Disagree
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

219.	By decreasing the highest temperature in the Carnot cycle, its efficiency is increased.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

220.	When a gas is heated at constant pressure
A.	its temperature will increase
B.	its volume will increase
C.	both temperature and volume will increase
D.	neither temperature not volume will increase
Answer» D. neither temperature not volume will increase

Discussion

221.	The fuel mostly used in cement industry and in metallurgical processes is
A.	wood charcoal
B.	bituminous coke
C.	pulverised coal
D.	coke
Answer» D. coke

Discussion

222.	Which of the following statement is correct according to Clausis statement of second law off thermodynamics?
A.	It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature.
B.	It is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature, without the aid of an external source.
C.	It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle.
D.	none of the above
Answer» C. It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle.

Discussion

223.	As per Charles' law, the volume of a given mass of a perfect gas varies __________ as its absolute temperature, when the absolute pressure remains constant.
A.	directly
B.	indirectly
C.	Can't say
D.	None of these
Answer» B. indirectly

Discussion

224.	The property of a working substance which increases or decreases as the heat is supplied or removed in a reversible manner, is known as
A.	enthalpy
B.	internal energy
C.	entropy
D.	external energy
Answer» D. external energy

Discussion

225.	The principal constituents of a fuel are
A.	carbon and hydrogen
B.	oxygen and hydrogen
C.	sulphur and oxygen
D.	sulphur and hydrogen
Answer» B. oxygen and hydrogen

Discussion

226.	Liquid fuels have higher calorific value than solid fuels.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» B. No

Discussion

227.	Carnot cycle consists of
A.	two constant volume and two isentropic processes
B.	two isothermal and two isentropic processes
C.	two constant pressure and two isentropic processes
D.	one constant volume, one constant pressure and two isentropic processes
Answer» C. two constant pressure and two isentropic processes

Discussion

228.	The free expansion process is __________ non-flow process.
A.	reversible
B.	irreversible
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

229.	The hard coke is obtained when carbonisation of coal is carried out at
A.	300° to 500°C
B.	500° to700°C
C.	700° to 900°C
D.	900° to 1100°C
Answer» E.

Discussion

230.	When a gas is heated, change takes place in
A.	pressure
B.	volume
C.	temperature
D.	all of these
Answer» E.

Discussion

231.	The __________ states that change of internal energy of a perfect gas is directly proportional to the change of temperature.
A.	Boyle's law
B.	Charle's law
C.	Gay-Lussac law
D.	Joule's law
Answer» E.

Discussion

232.	The absolute zero pressure can be attained at a temperature of
A.	0°C
B.	273°C
C.	273 K
D.	none of these
Answer» E.

Discussion

233.	If in the equation pvn = C, the value of n = ∝ , then the process is called
A.	constant volume process
B.	adiabatic process
C.	constant pressure process
D.	isothermal process
Answer» B. adiabatic process

Discussion

234.	The heat energy stored in the gas and used for raising the temperature of the gas is known as
A.	external energy
B.	internal energy
C.	kinetic energy
D.	molecular energy
Answer» C. kinetic energy

Discussion

235.	Energy can neither be created nor destroyed, but it can be transformed from one form to another. This statement is known as
A.	Zeroth law of thermodynamics
B.	First law of thermodynamics
C.	Second law of thermodynamics
D.	Kinetic theory of gases
Answer» C. Second law of thermodynamics

Discussion

236.	During which of the following process does heat rejection takes place in Carnot cycle?
A.	Isothermal expansion
B.	Isentropic expansion
C.	Isothermal compression
D.	Isentropic compression
Answer» D. Isentropic compression

Discussion

237.	A mixture of gas expands from 0.03 m³ to 0.06 m³ at a constant pressure of 1 MPa and absorbs 84 kJ of heat during the process. The change in internal energy of the mixture is
A.	30 kJ
B.	54 kJ
C.	84 kJ
D.	114 kJ
Answer» C. 84 kJ

Discussion

238.	For the constant pressure and heat input, the air standard efficiency of gas power cycle is in the order
A.	Dual cycle, Diesel cycle, Otto cycle
B.	Otto cycle, Diesel cycle, Dual cycle
C.	Dual cycle, Otto cycle, Diesel cycle
D.	Diesel cycle, Otto cycle, Dual cycle
Answer» B. Otto cycle, Diesel cycle, Dual cycle

Discussion

239.	The polytropic index (n) is given by
A.	log (p1p2)/log (v1v2)
B.	log (p2/ p1)/log (v1/ v2)
C.	log (v1/ v2)/ log (p1/p2)
D.	log [(p1v1)/(p2v2)]
Answer» C. log (v1/ v2)/ log (p1/p2)

Discussion

240.	The atomic mass of sulphur is
A.	12
B.	14
C.	16
D.	32
Answer» E.

Discussion

241.	The heat and mechanical energies are mutually convertible. This statement was established by
A.	Boyle
B.	Charles
C.	Joule
D.	none of these
Answer» D. none of these

Discussion

242.	A cycle consisting of two constant pressure and two isothermal processes is known as Ericsson cycle.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

243.	The area under the temperature-entropy curve (i. e. T - s curve) of any thermodynamic process represents the workdone during the process.
A.	Agree
B.	Disagree
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

244.	A cycle consisting of two isothermal and two isentropic processes, is known as
A.	Carnot cycle
B.	Stirling cycle
C.	Ericsson cycle
D.	Joule cycle
Answer» B. Stirling cycle

Discussion

245.	When the gas is cooled at constant pressure,
A.	its temperature increases but volume decreases
B.	its volume increases but temperature decreases
C.	both temperature and volume increases
D.	both temperature and volume decreases
Answer» E.

Discussion

246.	When the gas is heated at constant pressure, the heat supplied
A.	increases the internal energy of the gas
B.	increases the temperature of the gas
C.	does some external work during expansion
D.	Both b and c
Answer» E.

Discussion

247.	A process, in which the working substance neither receives nor gives out heat to its surroundings during its expansion or compression, is called
A.	isothermal process
B.	hyperbolic process
C.	adiabatic process
D.	polytropic process
Answer» D. polytropic process

Discussion

248.	According to Regnault's law, the specific heat at constant pressure (cp) and specific heat at constant volume (cv) __________ with the change in pressure and temperature of the gas.
A.	change
B.	do not change
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

249.	A close cycle gas turbine gives __________ efficiency as compared to an open cycle gas turbine.
A.	same
B.	lower
C.	higher
D.	None of these
Answer» D. None of these

Discussion

250.	Which of the following gas has the highest calorific value?
A.	Coal gas
B.	Producer gas
C.	Mond gas
D.	Blast furnace gas
Answer» B. Producer gas

Discussion

Explore topic-wise MCQs in Graduate Aptitude Test (GATE).

In closed cycle gas turbine, the air is compressed

The __________ is obtained when carbonisation of coal is carried out at 500° to 700° C.

In S. I. units, the value of the universal gas constant is

The heat flows from a cold body to a hot body with the aid of an external source. This statement is given by

The lower calorific value of fuel may be obtained by adding the heat of steam formed during combustion to the higher calorific value.

The work ratio of a gas turbine plant is given by

The efficiency of the dual combustion cycle for the same compression ratio, is __________ Diesel cycle.

When a perfect gas is expanded through an aperture of minute dimensions, the process is known as

The gas in cooling chamber of a closed cycle gas turbine is cooled at

The state of a substance whose evaporation from its liquid state is partial, is known as steam.

The unit of energy is S. I. units is

A path 1-2-3 is given. A system absorbs 100 kJ as heat and does 60 kJ of work while along the path 1-4-3, it does 20 kJ of work. The heat absorbed during the cycle 1-4-3 is

Both the Ericsson and Joule's cycle have two constant pressure processes.

Which of the following is the correct statement?

According to Gay-Lussac law, the absolute pressure of a given mass of a perfect gas varies __________ as its absolute temperature, when the volume remains constant.

Briquetted coal is produced from the finely ground coal by moulding under pressure with or without a binding material.

A closed cycle gas turbine works on Joule's cycle.

Coke oven gas is obtained by burning coke in an oven.

By decreasing the highest temperature in the Carnot cycle, its efficiency is increased.

When a gas is heated at constant pressure

The fuel mostly used in cement industry and in metallurgical processes is

Which of the following statement is correct according to Clausis statement of second law off thermodynamics?

As per Charles' law, the volume of a given mass of a perfect gas varies __________ as its absolute temperature, when the absolute pressure remains constant.

The property of a working substance which increases or decreases as the heat is supplied or removed in a reversible manner, is known as

The principal constituents of a fuel are

Liquid fuels have higher calorific value than solid fuels.

Carnot cycle consists of

The free expansion process is __________ non-flow process.

The hard coke is obtained when carbonisation of coal is carried out at

When a gas is heated, change takes place in

The __________ states that change of internal energy of a perfect gas is directly proportional to the change of temperature.

The absolute zero pressure can be attained at a temperature of

If in the equation pvn = C, the value of n = ∝ , then the process is called

The heat energy stored in the gas and used for raising the temperature of the gas is known as

Energy can neither be created nor destroyed, but it can be transformed from one form to another. This statement is known as

During which of the following process does heat rejection takes place in Carnot cycle?

A mixture of gas expands from 0.03 m³ to 0.06 m³ at a constant pressure of 1 MPa and absorbs 84 kJ of heat during the process. The change in internal energy of the mixture is

For the constant pressure and heat input, the air standard efficiency of gas power cycle is in the order

The polytropic index (n) is given by

The atomic mass of sulphur is

The heat and mechanical energies are mutually convertible. This statement was established by

A cycle consisting of two constant pressure and two isothermal processes is known as Ericsson cycle.

The area under the temperature-entropy curve (i. e. T - s curve) of any thermodynamic process represents the workdone during the process.

A cycle consisting of two isothermal and two isentropic processes, is known as

When the gas is cooled at constant pressure,

When the gas is heated at constant pressure, the heat supplied

A process, in which the working substance neither receives nor gives out heat to its surroundings during its expansion or compression, is called

According to Regnault's law, the specific heat at constant pressure (cp) and specific heat at constant volume (cv) __________ with the change in pressure and temperature of the gas.

A close cycle gas turbine gives __________ efficiency as compared to an open cycle gas turbine.

Which of the following gas has the highest calorific value?