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

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

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

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 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

by heating wood with a limited supply of air to a temperature not less than 280°C

when coal is first dried and then crushed to a fine powder by pulverising machine

from the finely ground coal by moulding under pressure with or without a binding material

when coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel

by heating wood with a limited supply of air to a temperature not less than 280°C

The universal gas constant (or molar constant) of a gas is the product of

atomic mass of the gas and the gas constant

molecular mass of the gas and the gas constant

atomic mass of the gas and the gas constant

molecular mass of the gas and the specific heat at constant pressure

molecular mass of the gas and the specific heat at constant volume

189 + Mcqs in Thermodynamics in Mechanical Engineering Page 3 McqOptions

101.	In an extensive property of a thermodynamic system
A.	extensive heat is transferred
B.	extensive work is done
C.	extensive energy is utilised
D.	none of these
Answer» E.

Discussion

102.	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

103.	By decreasing the highest temperature in the Carnot cycle, its efficiency is increased.
A.	True
B.	False
Answer» C.

Discussion

104.	Workdone during adiabatic expansion is given by (where , = Pressure, volume and temperature for the initial condition of gas, , , = Corresponding values for the final condition of gas, = Gas constant, and γ = Ratio of specific heats)
A.	all of these
Answer» E.

Discussion

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

Discussion

106.	Those substances which have so far not been resolved by any means into other substances of simpler form are called
A.	elements
B.	compounds
C.	atoms
D.	molecules
Answer» B. compounds

Discussion

107.	Kelvin-Planck's law deals with
A.	conservation of work
B.	conservation of heat
C.	conversion of heat into work
D.	conversion of work into heat
Answer» D. conversion of work into heat

Discussion

108.	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
Answer» B. indirectly

Discussion

109.	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

110.	A process, in which the temperature of the working substance remains constant during its expansion or compression, is called
A.	isothermal process
B.	hyperbolic process
C.	adiabatic process
D.	polytropic process
Answer» B. hyperbolic process

Discussion

111.	The ratio of root mean square velocity to average velocity of gas molecules at a particular temperature is
A.	0.086
B.	1.086
C.	3.086
D.	4.086
Answer» C. 3.086

Discussion

112.	One kg of sulphur requires 1 kg of oxygen for complete combustion and produces 2 kg of sulphur dioxide.
A.	True
B.	False
Answer» B. False

Discussion

113.	The change of entropy, when heat is absorbed by the gas, is
A.	positive
B.	negative
C.	positive or negative
Answer» B. negative

Discussion

114.	A machine which violates the first law of thermodynamics is known as perpetual motion machine of the second kind.
A.	Correct
B.	Incorrect
Answer» C.

Discussion

115.	Both the Ericsson and Joule's cycle have two constant pressure processes.
A.	True
B.	False
Answer» B. False

Discussion

116.	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

117.	Steam coal is a
A.	pulverised coal
B.	brown coal
C.	coking bituminous coal
D.	non-coking bituminous coal
Answer» E.

Discussion

118.	The atomic mass of nitrogen is __________ oxygen.
A.	equal to
B.	less than
C.	more than
Answer» C. more than

Discussion

119.	Petrol is distilled at
A.	65° to 220°C
B.	220° to 345°C
C.	345° to 470°C
D.	470° to 550°C
Answer» B. 220° to 345°C

Discussion

120.	If the carbon content in the bituminous coal is 78 to 81%, it is said to be coking bituminous coal.
A.	Agree
B.	Disagree
Answer» C.

Discussion

121.	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

122.	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.
A.	Correct
B.	Incorrect
Answer» B. Incorrect

Discussion

123.	One kilowatt is equal to
A.	1 N-m/s
B.	100 N-m
C.	1000 N-m/s
D.	1 x 10
E.	N-m/s
Answer» D. 1 x 10

Discussion

124.	Second law of thermodynamics defines
A.	heat
B.	work
C.	internal energy
D.	entropy
Answer» E.

Discussion

125.	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

126.	A closed cycle gas turbine works on Joule's cycle.
A.	True
B.	False
Answer» B. False

Discussion

127.	The efficiency of Diesel cycle increases with increase in cut-off.
A.	Yes
B.	No
Answer» C.

Discussion

128.	The workdone in a free expansion process is zero.
A.	True
B.	False
Answer» B. False

Discussion

129.	The fuel mostly used in blast furnace for extracting pig iron from iron ores is
A.	hard coke
B.	soft coke
C.	pulverised coal
D.	bituminous coal
Answer» B. soft coke

Discussion

130.	The change of entropy, when heat is removed from the gas, is positive.
A.	Yes
B.	No
Answer» C.

Discussion

131.	It is __________ to make an engine working on a Carnot cycle.
A.	possible
B.	impossible
Answer» C.

Discussion

132.	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

133.	The throttling process is __________ process.
A.	reversible
B.	irreversible
C.	reversible or irreversible
Answer» C. reversible or irreversible

Discussion

134.	The air standard efficiency of an Otto cycle is given by (where = Compression ratio, and γ = Ratio of specific heats)
A.	1 -
B.	1 +
Answer» D.

Discussion

135.	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

136.	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

137.	When wood is heated with a limited supply of air to a temperature not less than 280°C, the resulting fuel is
A.	coke
B.	wood charcoal
C.	bituminous coal
D.	briquetted coal
Answer» C. bituminous coal

Discussion

138.	The amount of heat required to raise the temperature of unit mass of a gas through one degree at constant pressure is called specific heat at constant pressure.
A.	True
B.	False
Answer» B. False

Discussion

139.	The change of entropy, when heat is removed from the gas, is negative.
A.	Yes
B.	No
Answer» B. No

Discussion

140.	Coke is produced
A.	when coal is first dried and then crushed to a fine powder by pulverising machine
B.	from the finely ground coal by moulding under pressure with or without a binding material
C.	when coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel
D.	by heating wood with a limited supply of air to a temperature not less than 280°C
Answer» D. by heating wood with a limited supply of air to a temperature not less than 280°C

Discussion

141.	The universal gas constant (or molar constant) of a gas is the product of
A.	molecular mass of the gas and the gas constant
B.	atomic mass of the gas and the gas constant
C.	molecular mass of the gas and the specific heat at constant pressure
D.	molecular mass of the gas and the specific heat at constant volume
Answer» B. atomic mass of the gas and the gas constant

Discussion

142.	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

143.	The ideal efficiency of simple gas turbine cycle depends upon pressure ratio.
A.	Yes
B.	No
Answer» B. No

Discussion

144.	A molecule consisting of one atom is known as
A.	monoatomic
B.	diatomic
C.	triatomic
D.	polyatomic
Answer» B. diatomic

Discussion

145.	A definite area or a space where some thermodynamic process takes place is known as
A.	thermodynamic system
B.	thermodynamic cycle
C.	thermodynamic process
D.	thermodynamic law
Answer» B. thermodynamic cycle

Discussion

146.	The amount of heat required to raise the temperature of __________ water through one degree is called kilojoule.
A.	1 g
B.	10 g
C.	100 g
D.	1000 g
Answer» E.

Discussion

147.	A cycle consisting of two constant pressure and two isothermal processes is known as Ericsson cycle.
A.	True
B.	False
Answer» B. False

Discussion

148.	A process of heating crude oil to a high temperature under a very high pressure to increase the yield of lighter distillates, is known as
A.	cracking
B.	carbonisation
C.	fractional distillation
D.	full distillation
Answer» B. carbonisation

Discussion

149.	If in the equation = , the value of = 1, then the process is called isothermal process.
A.	True
B.	False
Answer» B. False

Discussion

150.	The specific volume of a system is an __________ property.
A.	extensive
B.	intensive
Answer» C.

Discussion

Explore topic-wise MCQs in Mechanical Engineering.

In an extensive property of a thermodynamic system

When a gas is heated at constant pressure

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

Workdone during adiabatic expansion is given by (where , = Pressure, volume and temperature for the initial condition of gas, , , = Corresponding values for the final condition of gas, = Gas constant, and γ = Ratio of specific heats)

In closed cycle gas turbine, the air is compressed

Those substances which have so far not been resolved by any means into other substances of simpler form are called

Kelvin-Planck's law deals with

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.

According to Avogadro's law

A process, in which the temperature of the working substance remains constant during its expansion or compression, is called

The ratio of root mean square velocity to average velocity of gas molecules at a particular temperature is

One kg of sulphur requires 1 kg of oxygen for complete combustion and produces 2 kg of sulphur dioxide.

The change of entropy, when heat is absorbed by the gas, is

A machine which violates the first law of thermodynamics is known as perpetual motion machine of the second kind.

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

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

Steam coal is a

The atomic mass of nitrogen is __________ oxygen.

Petrol is distilled at

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

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

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.

One kilowatt is equal to

Second law of thermodynamics defines

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

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

The efficiency of Diesel cycle increases with increase in cut-off.

The workdone in a free expansion process is zero.

The fuel mostly used in blast furnace for extracting pig iron from iron ores is

The change of entropy, when heat is removed from the gas, is positive.

It is __________ to make an engine working on a Carnot cycle.

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

The throttling process is __________ process.

The air standard efficiency of an Otto cycle is given by (where = Compression ratio, and γ = Ratio of specific heats)

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

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

When wood is heated with a limited supply of air to a temperature not less than 280°C, the resulting fuel is

The amount of heat required to raise the temperature of unit mass of a gas through one degree at constant pressure is called specific heat at constant pressure.

The change of entropy, when heat is removed from the gas, is negative.

Coke is produced

The universal gas constant (or molar constant) of a gas is the product of

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

The ideal efficiency of simple gas turbine cycle depends upon pressure ratio.

A molecule consisting of one atom is known as

A definite area or a space where some thermodynamic process takes place is known as

The amount of heat required to raise the temperature of __________ water through one degree is called kilojoule.

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

A process of heating crude oil to a high temperature under a very high pressure to increase the yield of lighter distillates, is known as

If in the equation = , the value of = 1, then the process is called isothermal process.

The specific volume of a system is an __________ property.