In an isothermal process,

there is no change in temperature

there is no change in internal energy

When a gas is heated at constant volume

neither temperature nor pressure will increase

both temperature and pressure will increase

neither temperature nor pressure will increase

For a perfect gas, according to Boyle's law (where p = Absolute pressure, v = Volume, and T = Absolute temperature)

v/T = constant, if p is kept constant

p v = constant, if T is kept constant

v/T = constant, if p is kept constant

p/T = constant, if v is kept constant

T/p = constant, if v is kept constant

Which of the following is the correct statement of the second law of thermodynamics?

It is impossible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work.

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

There is a definite amount of mechanical energy, which can be obtained from a given quantity of heat energy.

The isothermal and adiabatic processes are regarded as

reversible or irreversible process

Diesel cycle consists of __________ processes.

two constant volume and two isentropic

two constant pressure and two isentropic

two constant volume and two isothermal

one constant pressure, one constant volume and two isentropic

The mass of flue gas per kg of fuel is the ratio of the

mass of carbon in 1 kg of fuel to the mass of carbon in 1 kg of flue gas

mass of oxygen in 1 kg of flue gas to the mass of oxygen in 1 kg of fuel

mass of oxygen in 1 kg of fuel to the mass of oxygen in 1 kg of flue gas

mass of carbon in 1 kg of flue gas to the mass of carbon in 1 kg of fuel

mass of carbon in 1 kg of fuel to the mass of carbon in 1 kg of flue gas

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

increasing the internal energy of gas

increasing the internal energy of gas and also for doing some external work

The absolute zero pressure will be

when molecular momentum of the system becomes zero

For the same maximum pressure and temperature,

Dual cycle is more efficient than Otto and Diesel cycles

Otto cycle is more efficient than Diesel cycle

Diesel cycle is more efficient than Otto cycle

Dual cycle is more efficient than Otto and Diesel cycles

Dual cycle is less efficient than Otto and Diesel cycles

An open system is one in which

neither the heat and work nor the mass of the working substance crosses the boundary of the system

heat and work crosses the boundary of the system, but the mass of the working substance does not crosses the boundary of the system

mass of the working substance crosses the boundary of the system but the heat and work does not crosses the boundary of the system

both the heat and work as well as mass of the working substance crosses the boundary of the system

neither the heat and work nor the mass of the working substance crosses the boundary of the system

The gas constant (R) is equal to the

difference of two specific heats

The increase in entropy of a system represents

increase in availability of energy

According to Avogadro's law

the product of the gas constant and the molecular mass of an ideal gas is constant

the sum of partial pressure of the mixture of two gases is sum of the two

equal volumes of all gases, at the same temperature and pressure, contain equal number of molecules

The amount of heat required to raise the temperature of 1 kg of water through one Kelvin is called

specific heat at constant volume

specific heat at constant pressure

In open cycle gas turbine plants

the indirect heat exchanger and cooler is avoided

direct combustion system is used

425 + Mcqs in Thermodynamics in Graduate Aptitude Test (GATE) Page 3 McqOptions

101.	Liquid fuels consist of hydrocarbons.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

102.	In an isothermal process,
A.	there is no change in temperature
B.	there is no change in enthalpy
C.	there is no change in internal energy
D.	all of these
Answer» E.

Discussion

103.	An open cycle gas turbine works on
A.	Carnot cycle
B.	Otto cycle
C.	Joule's cycle
D.	Stirling cycle
Answer» D. Stirling cycle

Discussion

104.	A perpetual motion machine of the first kind is __________ according to first law of thermodynamics.
A.	possible
B.	impossible
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

105.	One kg of carbon requires 8/3 kg of oxygen for its complete combustion and produces 11/3 kg of carbon dioxide gas.
A.	Agree
B.	Disagree
C.	Can't say
D.	None of these
Answer» B. Disagree

Discussion

106.	A triatomic molecule consists of __________ atoms.
A.	one
B.	two
C.	three
D.	four
Answer» D. four

Discussion

107.	According to kinetic theory of gases, the velocity of molecules __________ with the increase in temperature.
A.	remains constant
B.	increases
C.	decreases
D.	None of these
Answer» C. decreases

Discussion

108.	When a gas is heated at constant volume
A.	its temperature will increase
B.	its pressure will increase
C.	both temperature and pressure will increase
D.	neither temperature nor pressure will increase
Answer» D. neither temperature nor pressure will increase

Discussion

109.	For a perfect gas, according to Boyle's law (where p = Absolute pressure, v = Volume, and T = Absolute temperature)
A.	p v = constant, if T is kept constant
B.	v/T = constant, if p is kept constant
C.	p/T = constant, if v is kept constant
D.	T/p = constant, if v is kept constant
Answer» B. v/T = constant, if p is kept constant

Discussion

110.	Which of the following is the correct statement of the second law of thermodynamics?
A.	It is impossible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work.
B.	It is impossible to transfer heat from a body at a lower temperature to a higher temperature, without the aid of an external source.
C.	There is a definite amount of mechanical energy, which can be obtained from a given quantity of heat energy.
D.	all of the above
Answer» E.

Discussion

111.	Boyle's law states that change of internal energy of a perfect gas is directly proportional to the change of temperature.
A.	Agree
B.	Disagree
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

112.	Which of the following is the extensive property of a thermodynamic system?
A.	Pressure
B.	Volume
C.	Temperature
D.	Density
Answer» C. Temperature

Discussion

113.	The entropy of water at 0°C is assumed to be
A.	1
B.	0
C.	-1
D.	10
Answer» C. -1

Discussion

114.	When a fluid is allowed to expand suddenly into a vaccum chamber through an orifice of large dimensions, the process is known as free expansion process.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

115.	The isothermal and adiabatic processes are regarded as
A.	reversible process
B.	irreversible process
C.	reversible or irreversible process
D.	none of these
Answer» B. irreversible process

Discussion

116.	Diesel cycle consists of __________ processes.
A.	two constant volume and two isentropic
B.	two constant pressure and two isentropic
C.	two constant volume and two isothermal
D.	one constant pressure, one constant volume and two isentropic
Answer» E.

Discussion

117.	The mass of flue gas per kg of fuel is the ratio of the
A.	mass of oxygen in 1 kg of flue gas to the mass of oxygen in 1 kg of fuel
B.	mass of oxygen in 1 kg of fuel to the mass of oxygen in 1 kg of flue gas
C.	mass of carbon in 1 kg of flue gas to the mass of carbon in 1 kg of fuel
D.	mass of carbon in 1 kg of fuel to the mass of carbon in 1 kg of flue gas
Answer» D. mass of carbon in 1 kg of fuel to the mass of carbon in 1 kg of flue gas

Discussion

118.	A process, in which the gas is heated or expanded in such a way that the product of its pressure and volume remains constant, is called
A.	isothermal process
B.	hyperbolic process
C.	adiabatic process
D.	polytropic process
Answer» C. adiabatic process

Discussion

119.	When gas is heated at constant pressure, the heat supplied is utilised in
A.	increasing the internal energy of gas
B.	doing some external work
C.	increasing the internal energy of gas and also for doing some external work
D.	none of the above
Answer» D. none of the above

Discussion

120.	The absolute zero pressure will be
A.	when molecular momentum of the system becomes zero
B.	at sea level
C.	at the temperature of - 273 K
D.	at the centre of the earth
Answer» B. at sea level

Discussion

121.	One kilowatt is equal to
A.	1 N-m/s
B.	100 N-m
C.	1000 N-m/s
D.	1 x 106 N-m/s
Answer» D. 1 x 106 N-m/s

Discussion

122.	Which of the following has the highest calorific value?
A.	Peat
B.	Lignite
C.	Bituminous coal
D.	Anthracite coal
Answer» E.

Discussion

123.	The blast furnace gas is a by-product in the production of pig iron in the blast furnace.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» B. No

Discussion

124.	The oxygen atom is __________ times heavier than the hydrogen atom.
A.	2
B.	4
C.	8
D.	16
Answer» E.

Discussion

125.	For the same maximum pressure and temperature,
A.	Otto cycle is more efficient than Diesel cycle
B.	Diesel cycle is more efficient than Otto cycle
C.	Dual cycle is more efficient than Otto and Diesel cycles
D.	Dual cycle is less efficient than Otto and Diesel cycles
Answer» C. Dual cycle is more efficient than Otto and Diesel cycles

Discussion

126.	An open system is one in which
A.	heat and work crosses the boundary of the system, but the mass of the working substance does not crosses the boundary of the system
B.	mass of the working substance crosses the boundary of the system but the heat and work does not crosses the boundary of the system
C.	both the heat and work as well as mass of the working substance crosses the boundary of the system
D.	neither the heat and work nor the mass of the working substance crosses the boundary of the system
Answer» D. neither the heat and work nor the mass of the working substance crosses the boundary of the system

Discussion

127.	The gas constant (R) is equal to the
A.	sum of two specific heats
B.	difference of two specific heats
C.	product of two specific heats
D.	ratio of two specific heats
Answer» C. product of two specific heats

Discussion

128.	One reversible heat engine operates between 1600 K and T₂ K and another reversible heat engine operates between T₂ K and 400 K. If both the engines have the same heat input and output, then temperature T₂ is equal to
A.	800K
B.	1000K
C.	1200K
D.	1400K
Answer» B. 1000K

Discussion

129.	The ratio of specific heat at constant pressure (cp) and specific heat at constant volume (cv) is always __________ one.
A.	equal to
B.	less than
C.	greater than
D.	None of these
Answer» D. None of these

Discussion

130.	The value of universal gas constant is same for all gases.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» B. No

Discussion

131.	The increase in entropy of a system represents
A.	increase in availability of energy
B.	increase in temperature
C.	decrease in pressure
D.	degradation of energy
Answer» E.

Discussion

132.	The entropy is a point function and thus it is a property of the same.
A.	Correct
B.	Incorrect
C.	Can't say
D.	None of these
Answer» B. Incorrect

Discussion

133.	According to kinetic theory of gases, the kinetic energy of translation of a molecule is proportional to
A.	T
B.	T
C.	1/T
D.	1/T
Answer» D. 1/T

Discussion

134.	The workdone in a free expansion process is zero.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

135.	The heat absorbed or rejected by the working substance is given by (where ds = Increase or decrease of entropy, T = Absolute temperature, and dQ = Heat absorbed or rejected)
A.	δQ = T.ds
B.	δQ = T/ds
C.	dQ = ds/T
D.	none of these
Answer» B. δQ = T/ds

Discussion

136.	Which of the following process can be made reversible with the help of a regenerator?
A.	Constant pressure process
B.	Constant volume process
C.	Constant pvn process
D.	all of these
Answer» E.

Discussion

137.	The throttling process is __________ process.
A.	reversible
B.	irreversible
C.	reversible or irreversible
D.	None of these
Answer» C. reversible or irreversible

Discussion

138.	The value of one bar (in S. I. units) is equal to
A.	1 x 102 N/m²
B.	1 x 103 N/m²
C.	1 x 104 N/m²
D.	1 x 105 N/m²
Answer» E.

Discussion

139.	A process, in which the gas is heated or expanded in such a way that product of its pressure and volume remains constant, is called isothermal process.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

140.	The atomic mass of an element is the number of times the atom of that element is heavier than the hydrogen atom.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

141.	The heating of a gas at constant pressure is governed by
A.	Boyle's law
B.	Charles' law
C.	Gay-Lussac law
D.	Avogadro's law
Answer» C. Gay-Lussac law

Discussion

142.	According to Avogadro's law
A.	the product of the gas constant and the molecular mass of an ideal gas is constant
B.	the sum of partial pressure of the mixture of two gases is sum of the two
C.	equal volumes of all gases, at the same temperature and pressure, contain equal number of molecules
D.	all of the above
Answer» D. all of the above

Discussion

143.	The absolute pressure of a given mass of a perfect gas varies inversely as its volume, when the temperature remains constant. This statement is known as Boyle's law.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» B. No

Discussion

144.	The entropy may be expressed as a function of
A.	pressure and temperature
B.	temperature and volume
C.	heat and work
D.	all of these
Answer» B. temperature and volume

Discussion

145.	The throttling process is an irreversible steady flow expansion process.
A.	Correct
B.	Incorrect
C.	Can't say
D.	None of these
Answer» B. Incorrect

Discussion

146.	The temperature at which the volume of a gas becomes zero is called
A.	absolute scale of temperature
B.	absolute zero temperature
C.	absolute temperature
D.	none of these
Answer» C. absolute temperature

Discussion

147.	The amount of heat required to raise the temperature of 1 kg of water through one Kelvin is called
A.	specific heat at constant volume
B.	specific heat at constant pressure
C.	kilo-Joule
D.	none of these
Answer» D. none of these

Discussion

148.	The heat supplied to the gaS at constant volume is (where m = Mass of gas, cv = Specific heat at constant volume, cp = Specific heat at constant pressure, T2 - T1 = Rise in temperature, and R = Gas constant)
A.	mR(T2 - T1)
B.	mcv(T2 - T1)
C.	mcp(T2 - T1)
D.	mcp(T2 + T1)
Answer» C. mcp(T2 - T1)

Discussion

149.	If the carbon content in the bituminous coal is 78 to 81%, it is said to be coking bituminous coal.
A.	Agree
B.	Disagree
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

150.	In open cycle gas turbine plants
A.	the indirect heat exchanger and cooler is avoided
B.	direct combustion system is used
C.	a condenser is used
D.	all of the above
Answer» E.

Discussion

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

Liquid fuels consist of hydrocarbons.

In an isothermal process,

An open cycle gas turbine works on

A perpetual motion machine of the first kind is __________ according to first law of thermodynamics.

One kg of carbon requires 8/3 kg of oxygen for its complete combustion and produces 11/3 kg of carbon dioxide gas.

A triatomic molecule consists of __________ atoms.

According to kinetic theory of gases, the velocity of molecules __________ with the increase in temperature.

When a gas is heated at constant volume

For a perfect gas, according to Boyle's law (where p = Absolute pressure, v = Volume, and T = Absolute temperature)

Which of the following is the correct statement of the second law of thermodynamics?

Boyle's law states that change of internal energy of a perfect gas is directly proportional to the change of temperature.

Which of the following is the extensive property of a thermodynamic system?

The entropy of water at 0°C is assumed to be

When a fluid is allowed to expand suddenly into a vaccum chamber through an orifice of large dimensions, the process is known as free expansion process.

The isothermal and adiabatic processes are regarded as

Diesel cycle consists of __________ processes.

The mass of flue gas per kg of fuel is the ratio of the

A process, in which the gas is heated or expanded in such a way that the product of its pressure and volume remains constant, is called

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

The absolute zero pressure will be

One kilowatt is equal to

Which of the following has the highest calorific value?

The blast furnace gas is a by-product in the production of pig iron in the blast furnace.

The oxygen atom is __________ times heavier than the hydrogen atom.

For the same maximum pressure and temperature,

An open system is one in which

The gas constant (R) is equal to the

One reversible heat engine operates between 1600 K and T₂ K and another reversible heat engine operates between T₂ K and 400 K. If both the engines have the same heat input and output, then temperature T₂ is equal to

The ratio of specific heat at constant pressure (cp) and specific heat at constant volume (cv) is always __________ one.

The value of universal gas constant is same for all gases.

The increase in entropy of a system represents

The entropy is a point function and thus it is a property of the same.

According to kinetic theory of gases, the kinetic energy of translation of a molecule is proportional to

The workdone in a free expansion process is zero.

The heat absorbed or rejected by the working substance is given by (where ds = Increase or decrease of entropy, T = Absolute temperature, and dQ = Heat absorbed or rejected)

Which of the following process can be made reversible with the help of a regenerator?

The throttling process is __________ process.

The value of one bar (in S. I. units) is equal to

A process, in which the gas is heated or expanded in such a way that product of its pressure and volume remains constant, is called isothermal process.

The atomic mass of an element is the number of times the atom of that element is heavier than the hydrogen atom.

The heating of a gas at constant pressure is governed by

According to Avogadro's law

The absolute pressure of a given mass of a perfect gas varies inversely as its volume, when the temperature remains constant. This statement is known as Boyle's law.

The entropy may be expressed as a function of

The throttling process is an irreversible steady flow expansion process.

The temperature at which the volume of a gas becomes zero is called

The amount of heat required to raise the temperature of 1 kg of water through one Kelvin is called

The heat supplied to the gaS at constant volume is (where m = Mass of gas, cv = Specific heat at constant volume, cp = Specific heat at constant pressure, T2 - T1 = Rise in temperature, and R = Gas constant)

If the carbon content in the bituminous coal is 78 to 81%, it is said to be coking bituminous coal.

In open cycle gas turbine plants