425 + Mcqs in Thermodynamics McqOptions

1.	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

2.	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

3.	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

4.	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

5.	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

6.	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

7.	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

8.	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

9.	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

10.	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

11.	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

12.	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

13.	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

14.	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

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

Discussion

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

Discussion

17.	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

18.	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

19.	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

20.	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

21.	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

22.	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

23.	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

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

Discussion

25.	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

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

Discussion

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

Discussion

28.	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

29.	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

30.	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

31.	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

32.	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

33.	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

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

Discussion

35.	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

36.	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

37.	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

38.	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

39.	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

40.	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

41.	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

42.	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

43.	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

44.	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

45.	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

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

Discussion

47.	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

48.	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

49.	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

50.	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 Testing Subject.

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