Select the wrong statement

An Otto cycle consists of two constant volume and two isentropic processes.

A Joule cycle consists of two constant volume and two isentropic processes.

An Otto cycle consists of two constant volume and two isentropic processes.

An Ericsson cycle consists of two constant pressure and two isothermal processes.

The amount of heat required to raise the temperature of the unit mass of gas through one degree at constant volume, is called

specific heat at constant pressure

specific heat at constant volume

specific heat at constant pressure

In a steady flow process, the ratio of

mass flow at inlet and outlet is same

Select the correct statement as per Charles' law

p/T = constant, if v 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

Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle

combustion is at constant volume

expansion and compression are isentropic

The efficiency of Carnot cycle depends upon

cut-off ratio and compression ratio

For the same compression ratio, the efficiency of dual combustion cycle is

less than Diesel cycle and greater than Otto cycle

greater than Diesel cycle and less than Otto cycle

less than Diesel cycle and greater than Otto cycle

The volumetric or molar specific heat at constant pressure is the product of

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

atomic mass of the gas and the gas constant

molecular mass of the gas and the gas constant

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 condition for the reversibility of a cycle is

the pressure and temperature of the working substance must not differ, appreciably, from those of the surroundings at any stage in the process

all the processes, taking place in the cycle of operation, must be extremely slow

the working parts of the engine must be friction free

Stirling cycle consists of

two constant pressure and two isothermal processes

two constant volume and two isentropic processes

two constant volume and two isothermal processes

two constant pressure and two isothermal processes

one constant volume, one constant pressure and two isentropic processes

The efficiency of the Carnot cycle may be increased by

decreasing the highest temperature

increasing the highest temperature

decreasing the highest temperature

increasing the lowest temperature

keeping the lowest temperature constant

425 + Mcqs in Thermodynamics in Graduate Aptitude Test (GATE) Page 7 McqOptions

301.	Wood charcoal is produced by heating the wood at 100°C.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

302.	Select the wrong statement
A.	A Joule cycle consists of two constant volume and two isentropic processes.
B.	An Otto cycle consists of two constant volume and two isentropic processes.
C.	An Ericsson cycle consists of two constant pressure and two isothermal processes.
D.	all of the above
Answer» B. An Otto cycle consists of two constant volume and two isentropic processes.

Discussion

303.	The efficiency of Otto cycle depends upon the specific heats of the working substance.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

304.	The amount of heat required to raise the temperature of the unit mass of gas through one degree at constant volume, is called
A.	specific heat at constant volume
B.	specific heat at constant pressure
C.	kilo Joule
D.	none of these
Answer» B. specific heat at constant pressure

Discussion

305.	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

306.	Stirling and Ericsson cycles are
A.	reversible cycles
B.	irreversible cycles
C.	semi-reversible cycles
D.	quasi-static cycles
Answer» B. irreversible cycles

Discussion

307.	In an ideal gas turbine plant, it is assumed that the compression and expansion processes are
A.	isothermal
B.	isentropic
C.	polytropic
D.	none of these
Answer» C. polytropic

Discussion

308.	In a steady flow process, the ratio of
A.	heat transfer is constant
B.	work transfer is constant
C.	mass flow at inlet and outlet is same
D.	all of these
Answer» E.

Discussion

309.	Select the correct statement as per Charles' law
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» C. p/T = constant, if v is kept constant

Discussion

310.	One kg of sulphur requires 1 kg of oxygen for complete combustion and produces 2 kg of sulphur dioxide.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

311.	The amount of heat generated per kg of fuel is known as
A.	calorific value
B.	heat energy
C.	lower calorific value
D.	higher calorific value
Answer» B. heat energy

Discussion

312.	If in the equation pvn = C, the value of n = 1, then the process is called isothermal process.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

313.	Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle
A.	combustion is at constant volume
B.	expansion and compression are isentropic
C.	maximum temperature is higher
D.	heat rejection is lower
Answer» E.

Discussion

314.	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
C.	Can't say
D.	None of these
Answer» B. False

Discussion

315.	When the finely ground coal is moulded under pressure with or without a binding material, the resulting fuel is called briquetted coal.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» B. No

Discussion

316.	One kg of carbon monoxide requires __________ kg of oxygen to produce 11/7 kg of carbon dioxide gas.
A.	All
B.	4/7
C.	11/4
D.	9/7
Answer» C. 11/4

Discussion

317.	The efficiency of Carnot cycle depends upon
A.	temperature limits
B.	pressure ratio
C.	volume compression ratio
D.	cut-off ratio and compression ratio
Answer» B. pressure ratio

Discussion

318.	The bomb calorimeter is used for finding the __________ calorific value of solid and liquid fuels.
A.	higher
B.	lower
C.	Can't say
D.	None of these
Answer» B. lower

Discussion

319.	The molecular mass expresssed in gram (i.e. 1 g - mole) of all gases, at N. T. P., occupies a volume of
A.	0.224 litres
B.	2.24 litres
C.	22.4 litres
D.	224 litres
Answer» D. 224 litres

Discussion

320.	All perfect gases change in volume by 1 / 273th of its original volume at 0°C for every 1°C change in temperature, when the pressure remains constant. This statement is called
A.	Boyle's law
B.	Charles' law
C.	Gay-Lussac law
D.	Joule's law
Answer» C. Gay-Lussac law

Discussion

321.	The value of cp/cv for air is
A.	1
B.	1.4
C.	1.8
D.	23
Answer» C. 1.8

Discussion

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

Discussion

323.	The efficiency of Ericsson cycle is __________ Carnot cycle.
A.	greater than
B.	less than
C.	equal to
D.	None of these
Answer» D. None of these

Discussion

324.	For the same compression ratio, the efficiency of dual combustion cycle is
A.	greater than Diesel cycle and less than Otto cycle
B.	less than Diesel cycle and greater than Otto cycle
C.	greater than Diesel cycle
D.	less than Diesel cycle
Answer» B. less than Diesel cycle and greater than Otto cycle

Discussion

325.	The compression ratio for petrol engines is
A.	3 to 6
B.	5 to 8
C.	15 to 20
D.	20 to 30
Answer» C. 15 to 20

Discussion

326.	The free expansion process is a constant enthalpy process.
A.	Correct
B.	Incorrect
C.	Can't say
D.	None of these
Answer» B. Incorrect

Discussion

327.	The volumetric or molar specific heat at constant pressure is the product of
A.	molecular mass of the gas and the specific heat at constant volume
B.	atomic mass of the gas and the gas constant
C.	molecular mass of the gas and the gas constant
D.	none of the above
Answer» E.

Discussion

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

Discussion

329.	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

330.	One kg of hydrogen requires 8 kg of oxygen and produces
A.	1 kg of water
B.	7 kg of water
C.	8 kg of water
D.	9 kg of water
Answer» E.

Discussion

331.	The natural solid fuel is
A.	wood
B.	coke
C.	anthracite coal
D.	pulverised coal
Answer» B. coke

Discussion

332.	The behaviour of super-heated vapour is similar to that of
A.	perfect gas
B.	air
C.	steam
D.	ordinary gas
Answer» B. air

Discussion

333.	One m³ of methane (CH₄) requires 2m³ of oxygen and produces 1m³ of carbon dioxide and 2m³ of water or steam.
A.	Correct
B.	Incorrect
C.	Can't say
D.	None of these
Answer» B. Incorrect

Discussion

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

Discussion

335.	The condition for the reversibility of a cycle is
A.	the pressure and temperature of the working substance must not differ, appreciably, from those of the surroundings at any stage in the process
B.	all the processes, taking place in the cycle of operation, must be extremely slow
C.	the working parts of the engine must be friction free
D.	all of the above
Answer» E.

Discussion

336.	A series of operations, which takes place in a certain order and restore the initial conditions at the end, is known as
A.	reversible cycle
B.	irreversible cycle
C.	thermodynamic cycle
D.	none of these
Answer» D. none of these

Discussion

337.	The atomic mass of oxygen is
A.	12
B.	14
C.	16
D.	32
Answer» D. 32

Discussion

338.	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

339.	The total energy of a molecule is shared equally by the various degrees of freedom possessed by it. This law is known as
A.	law of equipartition of energy
B.	law of conservation of energy
C.	law of degradation of energy
D.	none of these
Answer» B. law of conservation of energy

Discussion

340.	The kinetic energy of molecules of a gas becomes zero at absolute zero temperature.
A.	Agree
B.	Disagree
C.	Can't say
D.	None of these
Answer» B. Disagree

Discussion

341.	For the same compression ratio, the efficiency of Diesel cycle is __________ Otto cycle.
A.	greater than
B.	less than
C.	equal to
D.	None of these
Answer» C. equal to

Discussion

342.	First law of thermodynamics deals with
A.	conservation of heat
B.	conservation of momentum
C.	conservation of mass
D.	conservation of energy
Answer» E.

Discussion

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

Discussion

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

Discussion

345.	The efficiency of the Carnot cycle may be increased by
A.	increasing the highest temperature
B.	decreasing the highest temperature
C.	increasing the lowest temperature
D.	keeping the lowest temperature constant
Answer» B. decreasing the highest temperature

Discussion

346.	The gas turbine cycle with regenerator improves
A.	thermal efficiency
B.	work ratio
C.	avoids pollution
D.	none of these
Answer» B. work ratio

Discussion

347.	The variables which control the physical properties of a perfect gas are
A.	pressure exerted by the gas
B.	volume occupied by the gas
C.	temperature of the gas
D.	all of these
Answer» E.

Discussion

348.	When coal is first dried and then crushed to a fine powder by pulverising machine, the resulting fuel is called
A.	wood charcoal
B.	bituminous coal
C.	briquetted coal
D.	none of these
Answer» E.

Discussion

349.	In a reversible adiabatic process, the ratio of T1/T2 is equal to
A.	(p2/p1)γ - 1/ γ
B.	(p1/p2)γ - 1/ γ
C.	(v2/v1)γ - 1/ γ
D.	(v1/v2)γ - 1/ γ
Answer» C. (v2/v1)γ - 1/ γ

Discussion

350.	The efficiency of Diesel cycle increases with increase in cut-off.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

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

Wood charcoal is produced by heating the wood at 100°C.

Select the wrong statement

The efficiency of Otto cycle depends upon the specific heats of the working substance.

The amount of heat required to raise the temperature of the unit mass of gas through one degree at constant volume, is called

Petrol is distilled at

Stirling and Ericsson cycles are

In an ideal gas turbine plant, it is assumed that the compression and expansion processes are

In a steady flow process, the ratio of

Select the correct statement as per Charles' law

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

The amount of heat generated per kg of fuel is known as

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

Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle

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.

When the finely ground coal is moulded under pressure with or without a binding material, the resulting fuel is called briquetted coal.

One kg of carbon monoxide requires __________ kg of oxygen to produce 11/7 kg of carbon dioxide gas.

The efficiency of Carnot cycle depends upon

The bomb calorimeter is used for finding the __________ calorific value of solid and liquid fuels.

The molecular mass expresssed in gram (i.e. 1 g - mole) of all gases, at N. T. P., occupies a volume of

All perfect gases change in volume by 1 / 273th of its original volume at 0°C for every 1°C change in temperature, when the pressure remains constant. This statement is called

The value of cp/cv for air is

Second law of thermodynamics defines

The efficiency of Ericsson cycle is __________ Carnot cycle.

For the same compression ratio, the efficiency of dual combustion cycle is

The compression ratio for petrol engines is

The free expansion process is a constant enthalpy process.

The volumetric or molar specific heat at constant pressure is the product of

A molecule consisting of one atom is known as

Coke is produced

One kg of hydrogen requires 8 kg of oxygen and produces

The natural solid fuel is

The behaviour of super-heated vapour is similar to that of

One m³ of methane (CH₄) requires 2m³ of oxygen and produces 1m³ of carbon dioxide and 2m³ of water or steam.

Kerosene is distilled at

The condition for the reversibility of a cycle is

A series of operations, which takes place in a certain order and restore the initial conditions at the end, is known as

The atomic mass of oxygen is

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

The total energy of a molecule is shared equally by the various degrees of freedom possessed by it. This law is known as

The kinetic energy of molecules of a gas becomes zero at absolute zero temperature.

For the same compression ratio, the efficiency of Diesel cycle is __________ Otto cycle.

First law of thermodynamics deals with

Stirling cycle consists of

The gas constant (R) is equal to the __________ of two specific heats.

The efficiency of the Carnot cycle may be increased by

The gas turbine cycle with regenerator improves

The variables which control the physical properties of a perfect gas are

When coal is first dried and then crushed to a fine powder by pulverising machine, the resulting fuel is called

In a reversible adiabatic process, the ratio of T1/T2 is equal to

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