STD 11 - Thermodynamics PYQs: JEE Mains Physics – Page 2

Showing 51–100 of 166 questions

51. 51. During an adiabatic process, if the pressure of a gas is found to be proportional to the cube of its absolute temperature, then the ratio of \(\frac{C_p}{C_V}\) for the gas is _______. 2024 Hard
52. 52. The given figure represents two isobaric processes for the same mass of an ideal gas, then ....
    2024 Hard
53. 53. The heat absorbed by a system in going through the given cyclic process is _______.
    2024 Hard
54. 54. The pressure and volume of an ideal gas are related as \(\mathrm{PV}^{3 / 2}=\mathrm{K}\) (Constant). The work done when the gas is taken from state \(A\left(P_1, V_1, T_1\right)\) to state \(\mathrm{B}\left(\mathrm{P}_2, \mathrm{~V}_2, \mathrm{~T}_2\right)\) is _______. 2024 Hard
55. 55. The specific heat at constant pressure of a real gas obeying \(\mathrm{PV}^2=\mathrm{RT}\) equation is _______. 2024 Hard
56. 56. The volume of an ideal gas \((\gamma=1.5)\) is changed adiabatically from \(5\) litres to \(4\) litres. The ratio of initial pressure to final pressure is _______. 2024 Hard
57. 57. Two different adiabatic paths for the same gas intersect two isothermal curves as shown in\(P-V\) diagram. The relation between the ratio \(\frac{V_a}{V_d}\) and the ratio \(\frac{V_b}{V_c}\) is _______.
    2024 Hard
58. 58. \(1\,g\) of a liquid is converted to vapour at \(3 \times 10^5\,Pa\) pressure. If \(10 \%\) of the heat supplied is used for increasing the volume by \(1600\,cm ^3\) during this phase change, then the increase in internal energy in the process will be \(............\,J\) 2023 Medium
59. 59. A bicycle tyre is filled with air having pressure of \(270\,kPa\) at \(27^{\circ}\,C\). The approximate pressure of the air in the tyre when the temperature increases to \(36^{\circ}\,C\) is \(............kPa\) 2023 Easy
60. 60. A Carnot engine operating between two reservoirs has efficiency \(\frac{1}{3}\). When the temperature of cold reservoir raised by \(x\), its efficiency decreases to \(\frac{1}{6}\). The value of \(x\), if the temperature of hot reservoir is \(99^{\circ}\,C\), will be \(........\,K\) 2023 Medium
61. 61. A Carnot engine with efficiency \(50\,\%\) takes heat from a source at \(600\,K\). In order to increase the efficiency to \(70\,\%\), keeping the temperature of sink same, the new temperature of the source will be \(.........\,K\) 2023 Medium
62. 62. A gas is compressed adiabatically, which one of the following statement is NOT true. 2023 Medium
63. 63. A sample of gas at temperature \(T\) is adiabatically expanded to double its volume. The work done by the gas in the process is \(\left(\right.\) given, \(\left.\gamma=\frac{3}{2}\right)\) : 2023 Medium
64. 64. A source supplies heat to a system at the rate of \(1000 \,W\). If the system performs work at a rate of \(200\,W\). The rate at which internal energy of the system increases \(.......\,W\) 2023 Easy
65. 65. A thermodynamic system is taken through cyclic process. The total work done in the process is \(.........\,J\)
    2023 Easy
66. 66. An engine operating between the boiling and freezing points of water will have \(1.\) efficiency more than \(27 \%\) \(2.\) efficiency less than the efficiency a Carnot engine operating between the same two temperatures. \(3.\) efficiency equal to \(27 \%\) \(4.\) efficiency less than \(27 \%\) 2023 Medium
67. 67. Consider two containers \(A\) and \(B\) containing monoatomic gases at the same Pressure \((P)\), Volume \((V)\) and Temperature \((T)\). The gas in \(A\) is compressed isothermally to \(\frac{1}{8}\) of its original volume while the gas \(B\) is compressed adiabatically to \(\frac{1}{8}\) of its original volume. The ratio of final pressure of gas in \(B\) to that of gas in \(A\) is ........... 2023 Medium
68. 68. Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason \(R\). Assertion A : Efficiency of a reversible heat engine will be highest at \(-273^{\circ} C\) temperature of cold reservoir. Reason \(R\) : The efficiency of Carnot's engine depends not only on temperature of cold reservoir but it depends on the temperature of hot reservoir too and is given as \(\eta=\left(1-\frac{ T _2}{ T _1}\right)\). In the light of the above statements, choose the correct answer from the options given below 2023 Medium
69. 69. Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason \(R\). Assertion \(A\) : If \(dQ\) and \(dW\) represent the heat supplied to the system and the work done on the system respectively. Then according to the first law of thermodynamics \(d Q=d U-d W\). Reason \(R :\) First law of thermodynamics is based on law of conservation of energy. In the light of the above statements, choose the correct answer from the option given below : 2023 Medium
70. 70. Given below are two statements: Statement \(I:\) If heat is added to a system, its temperature must increase. Statement \(II:\) If positive work is done by a system in a thermodynamic process, its volume must increase. In the light of the above statements, choose the correct answer from the options given below 2023 Medium
71. 71. Heat is given to an ideal gas in an isothermal process. \(A.\) Internal energy of the gas will decrease. \(B.\) Internal energy of the gas will increase. \(C.\) Internal energy of the gas will not change. \(D.\) The gas will do positive work. \(E.\) The gas will do negative work. Choose the correct answer from the options given below : 2023 Medium
72. 72. Match List \(I\) with List \(II\) :

    List \(I\)	List \(II\)
    \(A\) Isothermal Process	\(I\) Work done by the gas decreases internal energy
    \(B\) Adiabatic Process	\(II\) No change in internal energy
    \(C\) Isochoric Process	\(III\) The heat absorbed goes partly to increase internal energy and partly to do work
    \(D\) Isobaric Process	\(IV\) No work is done on or by the gas

    Choose the correct answer from the options given below : 2023 Medium
73. 73. The initial pressure and volume of an ideal gas are \(P_0\) and \(V_0\). The final pressure of the gas when the gas is suddenly compressed to volume \(\frac{ V _0}{4}\) will be (Given \(\gamma=\) ratio of specific heats at constant pressure and at constant volume) 2023 Medium
74. 74. The pressure of a gas changes linearly with volume from \(A\) to \(B\) as shown in figure. If no heat is supplied to or extracted from the gas then change in the internal energy of the gas will be \(............\,J\)
    2023 Medium
75. 75. The thermodynamic process, in which internal energy of the system remains constant is ........... 2023 Easy
76. 76. Under isothermal condition, the pressure of a gas is given by \(P = aV ^{-3}\), where \(a\) is a constant and \(V\) is the volume of the gas. The bulk modulus at constant temperature is equal to \(..........\,P\) 2023 Hard
77. 77. Work done by a Carnot engine operating between temperatures \(127^{\circ}\,C\) and \(27^{\circ}\,C\) is \(2\,kJ\). The amount of heat transferred to the engine by the reservoir is \(........\,kJ\) 2023 Medium
78. 78. \(300 \,cal\). of heat is given to a heat engine and it rejects \(225 \,cal\). of heat. If source temperature is \(227^{\circ} C\), then the temperature of sink will be____\({ }^{\circ} C\). 2022 Medium
79. 79. A Carnot engine has efficiency of \(50 \%\). If the temperature of sink is reduced by \(40^{\circ} C\), its efficiency increases by \(30 \%\). The temperature of the source will be\(....K\) 2022 Medium
80. 80. A Carnot engine take \(5000 \,k\,cal\) of heat from a reservoir at \(727\,^{\circ}C\) and gives heat to a \(\operatorname{sink}\) at \(127\,^{\circ}C\). The work done by the engine is \(.......... \times 10^{6}\,J\) 2022 Medium
81. 81. A Carnot engine whose heat \(\operatorname{sinks}\) at \(27\,^{\circ} C\), has an efficiency of \(25 \%\). By how many degrees should the temperature of the source be changed to increase the efficiency by \(100 \%\) of the original efficiency \(?\) 2022 Hard
82. 82. A certain amount of gas of volume \(V\) at \(27^{o}\,C\) temperature and pressure \(2 \times 10^{7} \;Nm ^{-2}\) expands isothermally until its volume gets doubled. Later it expands adiabatically until its volume gets redoubled. The final pressure of the gas will be  (Use \(\gamma=1.5\) ) 2022 Medium
83. 83. A diatomic gas \((\gamma=1.4)\) does \(400 J\) of work when it is expanded isobarically. The heat given to the gas in the process is ............ \(J\) 2022 Medium
84. 84. A heat engine operates with the cold reservoir at temperature \(324 K\). The minimum temperature of the hot reservoir, if the heat engine takes \(300 \; J\) heat from the hot reservoir and delivers \(180 \; J\) heat to the cold reservoir per cycle, is \(\dots \; K .\) 2022 Medium
85. 85. A monoatomic gas at pressure \(P\) and volume \(V\) is suddenly compressed to one eighth of its original volume. The final pressure at constant entropy will be \(.....P\) 2022 Hard
86. 86. A sample of an ideal gas is taken through the cyclic process \(ABCA\) as shown in figure. It absorbs, \(40\,J\) of heat during the part \(A B\), no heat during \(BC\) and rejects \(60\,J\) of heat during \(CA\). \(A\) work \(50\,J\) is done on the gas during the part \(BC\). The internal energy of the gas at \(A\) is \(1560\,J\). The work done by the gas during the part \(CA\) is.............\(J\)
    2022 Medium
87. 87. A thermodynamic system is taken from an original state \(D\) to an intermediate state \(E\) by the linear process shown in the figure. Its volume is then reduced to the original volume from \(E\) to \(F\) by an isobaric process. The total work done by the gas from \(D\) to \(E\) to \(F\) will be \(......J\)
    2022 Medium
88. 88. Consider the efficiency of Carnot's engine is given by \(\eta=\frac{\alpha \beta}{\sin \theta} \log _{e} \frac{\beta x}{k T}\), where \(\alpha\) and \(\beta\) are constants. If \(T\) is temperature, \(k\) is Boltzman constant, \(\theta\) is angular displacement and \(x\) has the dimensions of length. Then, choose the incorrect option. 2022 Hard
89. 89. Given below are two statement  Statement \(-I\) : What \(\mu\) amount of an ideal gas undergoes adiabatic change from state \(\left( P _{1}, V _{1}, T _{1}\right)\) to state \(\left( P _{2}, V _{2}, T _{2}\right)\), the work done is \(W =\frac{1 R \left( T _{2}- T _{1}\right)}{1-\gamma}\), where \(\gamma=\frac{ C _{ P }}{ C _{ V }}\) and \(R =\) universal gas constant, Statement \(-II\) : In the above case. when work is done on the gas. the temperature of the gas would rise. Choose the correct answer from the options given below 2022 Medium
90. 90. In \(1^{\text {st }}\) case, Carnot engine operates between temperatures \(300\,K\) and \(100\,K\). In \(2^{\text {nd }}\) case, as shown in the figure, a combination of two engines is used. The efficiency of this combination (in \(2^{\text {ad }}\) case) will be.
    2022 Medium
91. 91. In a carnot engine, the temperature of reservoir is \(527^{\circ} C\) and that of \(\operatorname{sink}\) is \(200 \; K\). If the workdone by the engine when it transfers heat from reservoir to sink is \(12000 \; kJ\), the quantity of heat absorbed by the engine from reservoir is \(\times 10^{6} \; J\) 2022 Medium
92. 92. Let \(\eta_{1}\) is the efficiency of an engine at \(T _{1}=447^{\circ}\,C\) and \(T _{2}=147^{\circ}\,C\) while \(\eta_{2}\) is the efficiency at \(T _{1}=947^{\circ}\,C\) and \(T _{2}=47^{\circ}\,C\). The ratio \(\frac{\eta_{1}}{\eta_{2}}\) will be. 2022 Medium
93. 93. Starting with the same initial conditions, an ideal gas expands from volume \(V_{1}\) to \(V_{2}\) in three different ways. The work done by the gas is \(W_{1}\) if the process is purely isothermal. \(W _{2}\). if the process is purely adiabatic and \(W _{3}\) if the process is purely isobaric. Then, choose the coned option 2022 Medium
94. 94. The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is ........ \(\%\) 2022 Medium
95. 95. The pressure \(P_{1}\) and density \(d_{1}\) of diatomic gas \(\left(\gamma=\frac{7}{5}\right)\) changes suddenly to \(P _{2}\left(> P _{1}\right)\) and \(d _{2}\) respectively during an adiabatic process. The temperature of the gas increases and becomes \(......\) times of its initial temperature.\(\left(\right.\) given \(\left.\frac{ d _{2}}{ d _{1}}=32\right)\) 2022 Medium
96. 96. A Carnot's engine working between \(400\, K\) and \(800\, K\) has a work output of \(1200\, J\) per cycle. The amount of heat energy supplied to the engine from the source in each cycle is ........... \(J\) 2021 Medium
97. 97. A diatomic gas, having \(C_{p}=\frac{7}{2} R\) and \(C _{ v }=\frac{5}{2} R ,\) is heated at constant pressure. The ratio \(dU : dQ : dW :\) 2021 Hard
98. 98. A heat engine operates between a cold reservoir at temperature \({T}_{2}=400\, {K}\) and a hot reservoir at temperature \({T}_{1} .\) It takes \(300 \,{J}\) of heat from the hot reservoir and delivers \(240\, {J}\) of heat to the cold reservoir in a cycle. The minimum temperature of the hot reservoir has to be \(....{K}\) 2021 Medium
99. 99. A refrigerator consumes an average \(35\, {W}\) power to operate between temperature \(-10^{\circ} {C}\) to \(25^{\circ} {C}\). If there is no loss of energy then how much average heat per second does it transfer? (in \({J} / {s}\)) 2021 Medium
100. 100. A reversible engine has an efficiency of \(\frac{1}{4}\). If the temperature of the sink is reduced by \(58^{\circ} {C}\), its efficiency becomes double. Calculate the temperature of the sink. (In \(^{\circ} {C}\)) 2021 Hard

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