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

The efficiency of a gas turbine is given by

(Actual temperature drop)/(Isentropic temperature drop)

(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)

An adiabatic process is one in which

no heat enters or leaves the gas

the temperature of the gas changes

the change in internal energy is equal to the mechanical workdone

Carbonisation of coal consists of

drying and crushing the coal to a fine powder

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

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

The main cause for the irreversibility is

heat transfer with a finite temperature difference

425 + Mcqs in Thermodynamics in Graduate Aptitude Test (GATE) Page 6 McqOptions

251.	The ideal efficiency of simple gas turbine cycle depends upon pressure ratio.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» B. No

Discussion

252.	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

253.	The molecular mass of a substance is the number of times a molecule of that substance is heavier than the hydrogen atom.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

254.	A cycle consisting of two constant pressure and two isentropic processes is known as
A.	Carnot cycle
B.	Stirling cycle
C.	Otto cycle
D.	none of these
Answer» E.

Discussion

255.	The unit of power in S.I. units is kilowatt.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

256.	Ericsson cycle consists of two constant pressure and two isothermal processes.
A.	Agree
B.	Disagree
C.	Can't say
D.	None of these
Answer» B. Disagree

Discussion

257.	The elements are made up of minute and chemically invisible particles as atoms.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

258.	The efficiency of a gas turbine 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» C. (Actual temperature drop)/(Isentropic temperature drop)

Discussion

259.	Equal volumes of all gases, at the same temperature and pressure, contain equal number of molecules. This statement is called Avogadro's law.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

260.	An adiabatic process is one in which
A.	no heat enters or leaves the gas
B.	the temperature of the gas changes
C.	the change in internal energy is equal to the mechanical workdone
D.	all of the above
Answer» E.

Discussion

261.	Water gas is obtained by passing air and a large amount of steam over waste coal at about 650°C.
A.	Correct
B.	Incorrect
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

262.	Which of the following is the lightest and most volatile liquid fuel?
A.	Gasoline
B.	Kerosene
C.	Fuel oil
D.	None of these
Answer» B. Kerosene

Discussion

263.	When the gas is heated at constant volume, the heat supplied increases the internal energy of the gas.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

264.	The processes occuring in open system which permit the transfer of mass to and from the system, are known as
A.	flow processes
B.	non-flow processes
C.	adiabatic processes
D.	none of these
Answer» B. non-flow processes

Discussion

265.	Which of the following has the minimum atomic mass?
A.	Oxygen
B.	Sulphur
C.	Nitrogen
D.	Carbon
Answer» E.

Discussion

266.	Workdone in a free expansion process is
A.	zero
B.	minimum
C.	maximum
D.	positive
Answer» B. minimum

Discussion

267.	The pressure exerted by an ideal gas is __________ of the kinetic energy of all the molecules contained in a unit volume of gas.
A.	one-half
B.	one-third
C.	two-third
D.	three-fourth
Answer» D. three-fourth

Discussion

268.	The constant pressure, constant volume and constant pvn processes are regarded as irreversible process.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

269.	All the commercial liquid fuels are derived from natural petroleum (or crude oil).
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

270.	A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as
A.	Carnot cycle
B.	Stirling cycle
C.	Otto cycle
D.	Diesel cycle
Answer» E.

Discussion

271.	The efficiency and work ratio of a simple gas turbine cycle are
A.	low
B.	very low
C.	high
D.	very high
Answer» C. high

Discussion

272.	There is a loss of heat in an irreversible process.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

273.	Workdone during adiabatic expansion is given by (where p1 v1, T1 = Pressure, volume and temperature for the initial condition of gas, p2, v2, T2 = Corresponding values for the final condition of gas, R = Gas constant, and γ = Ratio of specific heats)
A.	A
B.	B
C.	C
D.	D
Answer» E.

Discussion

274.	The heat absorbed during a polytropic process is
A.	A
B.	B
C.	C
D.	D
Answer» E.

Discussion

275.	Which of the following represents Otto cycle on temperature - entropy (T - s) diagram?
A.	A
B.	B
C.	C
D.	D
Answer» D. D

Discussion

276.	The absolute zero temperature is taken as
A.	-273°C
B.	273°C
C.	237°F
D.	-237°F
Answer» B. 273°C

Discussion

277.	The specific heat of water is
A.	1.817
B.	2512
C.	4.187
D.	none of these
Answer» D. none of these

Discussion

278.	Carbonisation of coal consists of
A.	drying and crushing the coal to a fine powder
B.	moulding the finely ground coal under pressure with or without a binding material
C.	heating the wood with a limited supply of air to temperature not less than 280°C
D.	none of the above
Answer» E.

Discussion

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

Discussion

280.	According to Gay-Lussac law for a perfect gas, p/T = constant, if v is kept constant.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

281.	If the value of n = 0 in the equation pvn = C, then the process is called
A.	constant volume process
B.	adiabatic process
C.	constant pressure process
D.	isothermal process
Answer» D. isothermal process

Discussion

282.	Which of the following gas is mostly used in town for street and domestic lighting and heating?
A.	Producer gas
B.	Coal gas
C.	Mond gas
D.	Coke oven gas
Answer» C. Mond gas

Discussion

283.	The value of gas constant (R) in S. I. units is
A.	0.287 J/kgK
B.	2.87 J/kgK
C.	28.7 J/kgK
D.	287 J/kgK
Answer» E.

Discussion

284.	The entropy __________ in an irreversible cyclic process.
A.	remains constant
B.	decreases
C.	increases
D.	None of these
Answer» D. None of these

Discussion

285.	According to Avogadro's law, the density of any two gases is __________ their molecular masses, if the gases are at the same temperature and pressure.
A.	equal to
B.	directly proportional to
C.	inversely proportional to
D.	None of these
Answer» C. inversely proportional to

Discussion

286.	When cut-off ratio is __________ the efficiency of Diesel cycle approaches to Otto cycle efficiency.
A.	zero
B.	1/5
C.	4/5
D.	1
Answer» B. 1/5

Discussion

287.	An isothermal process is governed by
A.	Boyle's law
B.	Charles' law
C.	Gay-Lussac law
D.	Avogadro's law
Answer» B. Charles' law

Discussion

288.	The efficiency of Diesel cycle approaches to Otto cycle efficiency when
A.	cut-off is increased
B.	cut-off is decreased
C.	cut-off is zero
D.	cut-off is constant
Answer» D. cut-off is constant

Discussion

289.	In the first law of thermodynamics, the total energy of the system remains constant.
A.	True
B.	False
C.	Can't say
D.	None of these
Answer» B. False

Discussion

290.	Coal gas is obtained by mixing coal and gas at ambient conditions.
A.	Yes
B.	No
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

291.	The efficiency of Diesel cycle increases with
A.	decrease in cut-off
B.	increase in cut-off
C.	constant cut-off
D.	none of these
Answer» B. increase in cut-off

Discussion

292.	The value of specific heat at constant pressure (cp) is __________ that of at constant volume (cv).
A.	less than
B.	equal to
C.	more than
D.	None of these
Answer» D. None of these

Discussion

293.	The atomic mass of nitrogen is __________ oxygen.
A.	equal to
B.	less than
C.	more than
D.	None of these
Answer» C. more than

Discussion

294.	When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel, the process is known as __________ of fuel.
A.	atomisation
B.	carbonisation
C.	Can't say
D.	None of these
Answer» C. Can't say

Discussion

295.	The main cause for the irreversibility is
A.	mechanical and fluid friction
B.	unrestricted expansion
C.	heat transfer with a finite temperature difference
D.	all of the above
Answer» E.

Discussion

296.	In a free expansion process,
A.	W1 - 2 = 0
B.	Q1 - 2 = 0
C.	dU = 0
D.	all of these
Answer» E.

Discussion

297.	The general gas equation is (where p = Pressure, v = Volume, m = mass, T = Absolute temperature, and R = Gas constant)
A.	pv = mRT
B.	pv = RTm
C.	pvm = C
D.	pv = (RT)m
Answer» B. pv = RTm

Discussion

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

Discussion

299.	In an irreversible process, there is a
A.	loss of heat
B.	no loss of heat
C.	gain of heat
D.	no gain of heat
Answer» B. no loss of heat

Discussion

300.	The work ratio of simple gas turbine cycle depends upon
A.	maximum cycle temperature
B.	minimum cycle temperature
C.	pressure ratio
D.	all of these
Answer» E.

Discussion

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

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

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

The molecular mass of a substance is the number of times a molecule of that substance is heavier than the hydrogen atom.

A cycle consisting of two constant pressure and two isentropic processes is known as

The unit of power in S.I. units is kilowatt.

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

The elements are made up of minute and chemically invisible particles as atoms.

The efficiency of a gas turbine is given by

Equal volumes of all gases, at the same temperature and pressure, contain equal number of molecules. This statement is called Avogadro's law.

An adiabatic process is one in which

Water gas is obtained by passing air and a large amount of steam over waste coal at about 650°C.

Which of the following is the lightest and most volatile liquid fuel?

When the gas is heated at constant volume, the heat supplied increases the internal energy of the gas.

The processes occuring in open system which permit the transfer of mass to and from the system, are known as

Which of the following has the minimum atomic mass?

Workdone in a free expansion process is

The pressure exerted by an ideal gas is __________ of the kinetic energy of all the molecules contained in a unit volume of gas.

The constant pressure, constant volume and constant pvn processes are regarded as irreversible process.

All the commercial liquid fuels are derived from natural petroleum (or crude oil).

A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as

The efficiency and work ratio of a simple gas turbine cycle are

There is a loss of heat in an irreversible process.

Workdone during adiabatic expansion is given by (where p1 v1, T1 = Pressure, volume and temperature for the initial condition of gas, p2, v2, T2 = Corresponding values for the final condition of gas, R = Gas constant, and γ = Ratio of specific heats)

The heat absorbed during a polytropic process is

Which of the following represents Otto cycle on temperature - entropy (T - s) diagram?

The absolute zero temperature is taken as

The specific heat of water is

Carbonisation of coal consists of

The efficiency of Stirling cycle is __________ Carnot cycle.

According to Gay-Lussac law for a perfect gas, p/T = constant, if v is kept constant.

If the value of n = 0 in the equation pvn = C, then the process is called

Which of the following gas is mostly used in town for street and domestic lighting and heating?

The value of gas constant (R) in S. I. units is

The entropy __________ in an irreversible cyclic process.

According to Avogadro's law, the density of any two gases is __________ their molecular masses, if the gases are at the same temperature and pressure.

When cut-off ratio is __________ the efficiency of Diesel cycle approaches to Otto cycle efficiency.

An isothermal process is governed by

The efficiency of Diesel cycle approaches to Otto cycle efficiency when

In the first law of thermodynamics, the total energy of the system remains constant.

Coal gas is obtained by mixing coal and gas at ambient conditions.

The efficiency of Diesel cycle increases with

The value of specific heat at constant pressure (cp) is __________ that of at constant volume (cv).

The atomic mass of nitrogen is __________ oxygen.

When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel, the process is known as __________ of fuel.

The main cause for the irreversibility is

In a free expansion process,

The general gas equation is (where p = Pressure, v = Volume, m = mass, T = Absolute temperature, and R = Gas constant)

The ratio of specific heat at constant pressure (cp) and specific heat at constant volume (cv) is

In an irreversible process, there is a

The work ratio of simple gas turbine cycle depends upon