Thermodynamics

Q1: In the first law of thermodynamics, the total energy of the system remains constant.

A True

B False

Q2: The efficiency and work ratio of a simple gas turbine cycle are

A low

B very low

C high

D very high

Q3: Which of the following represents Otto cycle on temperature - entropy (T - s) diagram?

A

B

C

D

Q4: Stirling and Ericsson cycles are

A reversible cycles

B irreversible cycles

C semi-reversible cycles

D quasi-static cycles

Q5: Workdone in a free expansion process is

A zero

B minimum

C maximum

D positive

Q6: 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

Q7: 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

Q8: The compression ratio for petrol engines is

A 3 to 6

B 5 to 8

C 15 to 20

D 20 to 30

Q9: The sum of internal energy (U) and the product of pressure and volume (p.v) is known as

A workdone

B entropy

C enthalpy

D none of these

Q10: 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

Q11: An isothermal process is governed by

A Boyle's law

B Charles' law

C Gay-Lussac law

D Avogadro's law

Q12: 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

Q13: When the gas is heated at constant volume, the heat supplied increases the internal energy of the gas.

A True

B False

Q14: Which of the following is correct?

A Absolute pressure = Gauge pressure + Atmospheric pressure

B Gauge pressure = Absolute pressure + Atmospheric pressure

C Atmospheric pressure = Absolute pressure + Gauge pressure

D Absolute pressure = Gauge pressure - Atmospheric pressure

Q15: All the commercial liquid fuels are derived from natural petroleum (or crude oil).

A True

B False

Q16: The specific heat of water is

A 1.817

B 2512

C 4.187

D none of these

Q17: 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

Q18: The universal gas constant of a gas is the product of molecular mass of the gas and the gas constant.

A Correct

B Incorrect

Q19: The entropy __________ in an irreversible cyclic process.

A remains constant

B decreases

C increases

Q20: 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

Q21: The most probable velocity of the gas molecules is given by

A

B

C

D

Q22: 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

Q23: The efficiency of Stirling cycle is __________ Carnot cycle.

A greater than

B less than

C equal to

Q24: The value of 1 mm of Hg is equal to

A 1.333 N/m2

B 13.33 N/m2

C 133.3 N/m2

D 1333 N/m2

Q25: 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

Q26: 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

Q27: 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

Q28: Which of the following has the minimum atomic mass?

A Oxygen

B Sulphur

C Nitrogen

D Carbon

Q29: The kinetic energy of molecules of a gas becomes zero at absolute zero temperature.

A Agree

B Disagree

Q30: 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

Q31: Coal gas is obtained by mixing coal and gas at ambient conditions.

A Yes

B No

Q32: 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

Q33: The constant pressure, constant volume and constant pvn processes are regarded as irreversible process.

A True

B False

Q34: There is no change in internal energy in an isothermal process.

A Correct

B Incorrect

Q35: 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

Q36: According to Gay-Lussac law for a perfect gas, p/T = constant, if v is kept constant.

A True

B False

Q37: 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

Q38: The atomic mass of oxygen is

A 12

B 14

C 16

D 32

Q39: 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

Q40: 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

Q41: The absolute zero temperature is taken as

A -273°C

B 273°C

C 237°F

D -237°F

Q42: Which of the following statement is incorrect?

A The liquid fuels consist of hydrocarbons.

B The liquid fuels have higher calorific value than solid fuels.

C The solid fuels have higher calorific value than liquid fuels.

D A good fuel should have low ignition point.

Q43: The behaviour of a perfect gas, undergoing any change in the variables which control physical properties, is governed by

A Boyle's law

B Charles' law

C Gay-Lussac law

D all of these

Q44: Water gas is obtained by passing air and a large amount of steam over waste coal at about 650°C.

A Correct

B Incorrect

Q45: The distillation carried out in such a way that the liquid with the lowest boiling point is first evaporated and recondensed, then the liquid with the next higher boiling point is then evaporated and recondensed, and so on until all the available liquid fuels are separately recovered in the sequence of their boiling points. Such a process is called

A cracking

B carbonisation

C fractional distillation

D full distillation

Q46: There is a loss of heat in an irreversible process.

A True

B False

Q47: 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

Q48: One kg of carbon requires 4/3 kg of oxygen and produces __________ kg of carbon monoxide gas.

A 8/3

B 11/3

C 11/7

D 7/3

Q49: 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

Q50: Which of the following is the lightest and most volatile liquid fuel?

A Gasoline

B Kerosene

C Fuel oil


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