MCQOPTIONS
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MCQOPTIONS
This section includes 425 Mcqs, each offering curated multiple-choice questions to sharpen your Graduate Aptitude Test (GATE) knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
An ideal refrigerator is to maintain ice-cream kept inside at -3°C. If room temperature is 27°C, calculate its coefficient of performance. |
| A. | 7 |
| B. | 6 |
| C. | 3 |
| D. | 9 |
| Answer» E. | |
| 52. |
In thermodynamics ___________ is not a state variable. |
| A. | density |
| B. | internal energy |
| C. | enthalpy |
| D. | Heat |
| Answer» E. | |
| 53. |
If temperature of the source is increased, the efficiency of Carnot engine |
| A. | Increases |
| B. | Degreases |
| C. | Remains Constant |
| D. | First increases and then becomes constant |
| Answer» B. Degreases | |
| 54. |
How much heat (in joules) would be required to raise the temperature of 500 g of an aluminum sphere from 20° C to 720° C? [Specific Heat Capacity of Aluminium is 900 J/(kgK)] |
| A. | 3.15 x 105 |
| B. | 3.15 x 107 |
| C. | 1.26 x 105 |
| D. | 1.26 x 107 |
| Answer» B. 3.15 x 107 | |
| 55. |
In isochoric processes, __________ is constant. |
| A. | volume |
| B. | mass |
| C. | pressure |
| D. | temperature |
| Answer» B. mass | |
| 56. |
A gas of 240 ml is heated from 27°C to 227° C. What will be it's new volume (in ml) if pressure is constant? |
| A. | 300 |
| B. | 144 |
| C. | 288 |
| D. | 400 |
| Answer» E. | |
| 57. |
In which Thermodynamic process the pressure is constant? |
| A. | Isothermal |
| B. | Isochoric |
| C. | Isobaric |
| D. | Adiabatic |
| Answer» D. Adiabatic | |
| 58. |
For a refrigerator, what is the heat released to the hot reservoir equal to? ('α' is the coefficient of performance of a refrigerator, 'Q2' is the heatextracted from the cold reservoir) |
| A. | Q2/(1+α) |
| B. | Q2(1+α)/α |
| C. | αQ2/(1+α) |
| D. | (1+α)/Q2 |
| Answer» C. αQ2/(1+α) | |
| 59. |
"It is impossible for any device that operates on a cycle to receive heat from a single reservoir and produce a net amount of work. This is the second law of thermodynamics statements expressed by |
| A. | Kelvin Plank |
| B. | Clausius |
| C. | Rankine |
| D. | Otto |
| Answer» B. Clausius | |
| 60. |
A process in which the ____________ of the system is kept fixed throughout is called an isothermal process |
| A. | temperature |
| B. | mass |
| C. | pressure |
| D. | volume |
| Answer» B. mass | |
| 61. |
If 1022 gas molecules each of mass 10-26 kg collide with a surface (perpendicular to it) elastically per second over an area 1 m2 with a speed 104 m/s, the pressure exerted by the gas molecules will be of the order of: |
| A. | 104 N/m2 |
| B. | 108 N/m2 |
| C. | 103 N/m2 |
| D. | 1016 N/m2 |
| Answer» B. 108 N/m2 | |
| 62. |
η = 1- (Q2/Q1), where 'Q1' is the heat input i.e., the heat absorbed by the heat engine in one complete cycle and 'Q2' is the heat lost to the environment. Here 'η' is ________________. |
| A. | Efficiency |
| B. | Cp/Cv |
| C. | Coefficient of performance |
| D. | Cv/Cp |
| Answer» B. Cp/Cv | |
| 63. |
Energy is formed on the Sun ________. |
| A. | By nuclear fission |
| B. | By nuclear fusion |
| C. | By oxidation reactions |
| D. | By degradation reactions |
| Answer» C. By oxidation reactions | |
| 64. |
In which Thermodynamic process is temperature constant? |
| A. | Isobaric |
| B. | sochoric |
| C. | Adiabatic |
| D. | Isothermal |
| Answer» E. | |
| 65. |
A gas is compressed in a cylinder by a movable piston to a volume one-half its original volume. During the process 300 kJ heat left the gas and internal energy remained the same. The work done on gas in N-m will be |
| A. | 300 N-m |
| B. | 300,000 N-m |
| C. | 30 N-m |
| D. | 3000 N-m |
| Answer» C. 30 N-m | |
| 66. |
2 kg of a monoatomic gas is at a pressure of 4 × 104 N/m2. The density of the gas is 8 kg/m3. What is the order of energy of the gas due to its thermal motion? |
| A. | 106 J |
| B. | 103 J |
| C. | 104 J |
| D. | 105 J |
| Answer» D. 105 J | |
| 67. |
A cylinder of radius R is surrounded by a cylindrical shell of inner radius R and outer radius 2R. The thermal conductivity of the material of the inner cylinder is K1 and that of the outer cylinder is K2. Assuming no loss of heat, the effective thermal conductivity of the system for heat flowing along the length of the cylinder is |
| A. | \(\frac{{{{\rm{K}}_1} + {{\rm{K}}_2}}}{2}\) |
| B. | \(\frac{{{{\rm{K}}_1} + 3{{\rm{K}}_2}}}{4}\) |
| C. | \(\frac{{2{{\rm{K}}_1} + 3{{\rm{K}}_2}}}{5}\) |
| D. | K1 + K2 |
| Answer» C. \(\frac{{2{{\rm{K}}_1} + 3{{\rm{K}}_2}}}{5}\) | |
| 68. |
If __________ between the system and the surroundings, the process is adiabatic. |
| A. | both heat and matter flows |
| B. | heat flows but matter does not flow |
| C. | neither heat nor matter flows |
| D. | matter flows but heat does not flow |
| Answer» D. matter flows but heat does not flow | |
| 69. |
A cyclic heat engine does 24kJ of work per cycle. If the efficiency of the engine is 0.8, then what will be the heat (in kJ) rejected per cycle? |
| A. | 30 |
| B. | 6 |
| C. | 19.2 |
| D. | 39.2 |
| Answer» C. 19.2 | |
| 70. |
In which Thermodynamic process is there no flow of heat between the system and the surroundings? |
| A. | Isobaric |
| B. | Isochoric |
| C. | Adiabatic |
| D. | Isothermal |
| Answer» D. Isothermal | |
| 71. |
A gas can be taken from A to B via two different processes ACB and ADB.When path ACB is used 60 J of heat flows into the system and 30 J of work is done by the system. If path ADB is used work done by the system is 10 J. The heat flow into the system in path ADB is: |
| A. | 40 J |
| B. | 80 J |
| C. | 100 J |
| D. | 20 J |
| Answer» B. 80 J | |
| 72. |
A cycle tire bursts suddenly. This represents an: |
| A. | Isothermal process |
| B. | Isobaric process |
| C. | Isochoric process |
| D. | Adiabatic process |
| Answer» E. | |
| 73. |
Assertion (A): The heat and work transfer cannot be expressed as difference between the end states.Reason (R): Heat and work are both exact differentials. |
| A. | Both (A) and (R) are individually true and (R) is the correct explanation of A |
| B. | Both (A) and (R) are individually true but (R) is NOT the correct explanation of (A) |
| C. | (A) is true but (R) is false |
| D. | (A) is false but (R) is true |
| Answer» D. (A) is false but (R) is true | |
| 74. |
In isobaric processes, the ___________ is constant. |
| A. | mass |
| B. | volume |
| C. | pressure |
| D. | temperature |
| Answer» D. temperature | |
| 75. |
In which Thermodynamic process is volume constant? |
| A. | Isochoric |
| B. | Isobaric |
| C. | Isothermal |
| D. | Adiabatic |
| Answer» B. Isobaric | |
| 76. |
An ideal material for making handle of cooking vessels must have |
| A. | large heat capacity and small conductivity |
| B. | small heat capacity and large conductivity |
| C. | small heat capacity and small conductivity |
| D. | large heat capacity and large conductivity |
| Answer» B. small heat capacity and large conductivity | |
| 77. |
A steam engine delivers 5.4 × 108J of work per minute and absorbs 3.6 × 109J of heat per minute from its boiler. What is the efficiency of the engine? |
| A. | 0.15 |
| B. | 0.75 |
| C. | 0.85 |
| D. | 0.55 |
| Answer» B. 0.75 | |
| 78. |
One molecule of oxygen consists of __________ atoms of oxygen. |
| A. | 2 |
| B. | 4 |
| C. | 8 |
| D. | 16 |
| Answer» B. 4 | |
| 79. |
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. | |
| 80. |
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 | |
| 81. |
The process is adiabatic, if the value of n in the equation pvn = C, is |
| A. | 0 |
| B. | 1 |
| C. | γ |
| D. | ∝ |
| Answer» D. ∝ | |
| 82. |
When a system changes its state from one equilibrium state to another equilibrium state, then the path of successive states through which the system has passed, is known as |
| A. | thermodynamic law |
| B. | thermodynamic process |
| C. | thermodynamic cycle |
| D. | none of these |
| Answer» C. thermodynamic cycle | |
| 83. |
The general law of expansion or compression is pvn = C, The process is said to be hyperbolic, if n is equal to |
| A. | 0 |
| B. | 1 |
| C. | γ |
| D. | ∝ |
| Answer» C. γ | |
| 84. |
To ensure complete and rapid combustion of a fuel, some quantity of air, in excess of the theoretical or minimum air is supplied. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» B. No | |
| 85. |
Charles' law states that all perfect gases change in volume by __________ of its original volume at 0° C for every 1° C change in temperature, when pressure remains constant. |
| A. | 1/27th |
| B. | 1/93th |
| C. | 1/173th |
| D. | 1/273th |
| Answer» E. | |
| 86. |
It is __________ to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work. |
| A. | possible |
| B. | impossible |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 87. |
Mond gas is obtained by |
| A. | partial combusion of coal, coke, anthracite coal or charcoal in a mixed air steam blast |
| B. | carbonisation of bituminous coal |
| C. | passing steam over incandescent coke |
| D. | passing air and a large amount of steam over waste coal at about 650°C |
| Answer» E. | |
| 88. |
The heat and work are mutually convertible. This statement is called __________ law of thermodynamics. |
| A. | Zeroth |
| B. | First |
| C. | Second |
| D. | None of these |
| Answer» C. Second | |
| 89. |
The area under the temperature-entropy curve (T - s curve) of any thermodynamic process represents |
| A. | heat absorbed |
| B. | heat rejected |
| C. | either (a) or (b) |
| D. | none of these |
| Answer» D. none of these | |
| 90. |
The specific heat at constant volume is |
| A. | the amount of heat required to raise the temperature of unit mass of gas through one degree, at constant pressure |
| B. | the amount of heat required to raise the temperature of unit mass of gas through one degree, at constant volume |
| C. | the amount of heat required to raise the temperature of 1 kg of water through one degree |
| D. | any one of the above |
| Answer» C. the amount of heat required to raise the temperature of 1 kg of water through one degree | |
| 91. |
The general gas energy equation is (where Q1 - 2 = Heat supplied, dU = Change in internal energy, and W1 - 2 = Work done in heat units) |
| A. | Q1 - 2 = dU + W1 - 2 |
| B. | Q1 - 2 = dU - W1 - 2 |
| C. | Q1 - 2 = dU/W1 - 2 |
| D. | Q1 - 2 = dU x W1 - 2 |
| Answer» B. Q1 - 2 = dU - W1 - 2 | |
| 92. |
The compression ratio for Diesel engines is |
| A. | 3 to 6 |
| B. | 5 to 8 |
| C. | 15 to 20 |
| D. | 20 to 30 |
| Answer» D. 20 to 30 | |
| 93. |
The expansion ratio (r) is the ratio of (where v1 = Volume at the beginning of expansion, and v2 = Volume at the end of expansion) |
| A. | v1/v2 |
| B. | v2/v1 |
| C. | (v1 + v2)/v1 |
| D. | (v1 + v2)/v2 |
| Answer» C. (v1 + v2)/v1 | |
| 94. |
The absolute pressure of a given mass of a perfect gas varies inversely as its volume, when the temperature remains constant. This statement is known as Charles' law. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 95. |
The measurement of a thermodynamic property known as temperature is based on |
| A. | Zeroth law of thermodynamics |
| B. | First law of thermodynamics |
| C. | Second law of thermodynamics |
| D. | none of these |
| Answer» B. First law of thermodynamics | |
| 96. |
The fuel mostly used in steam boilers is |
| A. | brown coal |
| B. | peat |
| C. | coking bituminous coal |
| D. | non-coking bituminous coal |
| Answer» E. | |
| 97. |
Liquid fuels have lower efficiency than solid fuels. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 98. |
The efficiency of Joule cycle is |
| A. | greater than Carnot cycle |
| B. | less than Carnot cycle |
| C. | equal to Carnot cycle |
| D. | none of these |
| Answer» C. equal to Carnot cycle | |
| 99. |
The efficiency of Diesel cycle depends upon |
| A. | temperature limits |
| B. | pressure ratio |
| C. | compression ratio |
| D. | cut-off ratio and compression ratio |
| Answer» E. | |
| 100. |
The heating and expanding of a gas is called thermodynamic system. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |