NEET
Physics
Heat and Thermodynamics
Previous Years Questions

An ideal gas follows a process described by the equation $$P{V^2} = C$$ from the initial $$({P_1},\,{V_1},\,{T_1})$$ to final $$({P_2},\,{V_2},\,{T_2}... Two rods one made of copper and other made of steel of same length and same cross sectional area are joined together. The thermal conductivity of copp... Three vessels of equal capacity have gases at the same temperature and pressure. The first vessel contains helium (monoatomic), the second contains fl... An ideal gas undergoes four different processes from the same initial state as shown in the figure below. Those processes are adiabatic, isothermal, i... The volume occupied by the molecules contained in 4.5 kg water at STP, if the intermolecular forces vanish away is A cup of coffee cools from 90$$^\circ$$C to 80$$^\circ$$C in t minutes, when the room temperature is 20$$^\circ$$C. The time taken by a similar cup of... Match Column - I and Column - II and choose the correct match from the given choices. Column - I Column - II (A) ... The average thermal energy for a mono-atomic gas is : (kB is Boltzmann constant and T absolute temperature) The mean free path for a gas, with molecular diameter d and number density n can be expressed as : A cylinder contains hydrogen gas at pressure 249 kPa and temperature 27$$^\circ $$CIts density is : (R = 8.3 J mol-1 K-1) The quantities of heat required to raise the temperature of two solid copper spheres of radii r1 and r2 (r1 = 1.5r2) through 1 K are in the ratio :... Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B i... In which of the following processes, heat is neither absorbed nor released by a system? Increase in tempertaure of a gas filled in a container would lead to : The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is A sample of 0.1 g of water at 100°C and normal pressure (1.013 × 105 N m–2) requires 54 cal of heat energy to convert to steam at 100°C. If the volum... The volume (V) of a monatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat absorbed by i... At what temperature will the rms speed of oxygen molecules become just sufficient for escaping from the Earth’s atmosphere? (Given : Mass of oxygen mo... Thermodynamic processes are indicated in the following diagram. Match the following .tg {border-collapse:collapse;border-spacing:0;border:none;widt... A gas mixture consists of 2 moles of O2 and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the total internal energy of the system ... A carnot engine having an efficiency of$${1 \over {10}}$$as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amou... One mole of an ideal monatomic gas undergoes a process described by the equation PV3 = constant. The heat capacity of the gas during this process is ... The temperature inside a refrigerator is t2 oC. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be ... A given sample of an ideal gas occupies a volume V at a pressure P and absolute temperature T. The mass of each molecule of the gas is m. Which of the... A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is ag... The molecules of a given mass of a gas have r.m.s. velocity of 2000 m s$$-$$1 at 27oC and 1.0$$ \times $$105 N m$$-$$2 pressure. When the temperatur... A refrigerator works between 4oC and 30oC. It is required to remove 600 calories of heat every second in order to keep the temperature of the refriger... An ideal gas is compressed to half its initial volume by means of several processes. Which of the process results in the maximum work done on the gas... The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is$$-$$20oC, the temperature of the surroundings to which it... Two vessels separately contain two ideal gases A and B at the same temperature, the pressure of A being twice that of B. Under such conditions, the de... A Carnot engine, having an efficiency of as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absor... The ratio of the specific heats$${{{C_p}} \over {{C_v}}} = \gamma $$in terms of degrees of freedom (n) is given by Figure below shows two paths that may be taken by a gas to go from a state A to a state C. In process AB, 400 J of heat is added to the system and in... One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure. The change in internal energy of the ga... A monatomic gas at a pressure P, having a volume V expands isothermally to a volume 2V and then adiabatically to a volume 16V. The final pressure of t... A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is ... The mean free path of molecules of a gas, (radius r) is inversely proportional to Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning? A system is taken from state a to state c by two paths adc and abc as shown in the figure. The internal energy at a is$${U_a} = 10\,J$$. Along the pa... Two Carnot engines A and B are operated in series. The engine A receives heat from the source at temperature T1 and rejects the heat to the sink at te... In a vessel, the gas is at pressure P. If the mass of all the molecules is halved and their speed is doubled, then the resultant pressure will be The amount of heat energy required to raise the temperature of 1 g of Helium at NTP, from T1K to T2K is During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of$${{{C_p}} \over {{C_p}}}\$...
In the given (V $$-$$ T) diagram, what is the relation between pressure P1 and P2? ...
A gas is taken through the cycle A $$\to$$ B $$\to$$ C $$\to$$ A, as shown. what is the net work done by the gas? ...
An ideal gas goes from state A to state B via three different processes as indicated in the P-V diagram. If Q1, Q2, Q3 indicate the heat absorbed by ...
One mole of an ideal gas goes from an initial state A to final state B via two processes : It first undergoes isothermal expansion from volume V to 3V...
A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is ...
A mass of diatomic gas $$(\gamma = 1.4)$$ at a pressure of 2 atmospheres is compressed adiabatically so that its temperature rises from 27oC to 927oC...
During an isothermal expansion, a confined ideal gas does $$-$$ 150 J of work against its surroundings. This implies that
When 1 kg of ice at 0oC melts to water at 0oC, the resulting change in its entropy, taking latent heat of ice to be 80 cal/oC, is ...
If cp and cv denote the specific heats (per unit mass of an ideal gas of molecular weight M, then
A monatomic gas at pressure P1 and volume V1 is compressed adiabatically to $${{1 \over 8}^{th}}$$ of its original volume. What is the final pressure ...
If $$\Delta$$U and $$\Delta$$W represent the increase in internal energy and work done by the system respectively in a thermodynamical process, whic...
The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is
In thermodynamic processes which of the following statements is not true ?
At 10oC the value of the density of a fixed mass of an ideal gas divided by it pressure is x. At 110oC this ratio is
If Q, E and W denote respectively the heat added, change in internal energy and the work done in a closed cyclic process, then
An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62oC, its efficiency is doubled. Temperatures of the source is ...
The molar specific heat at constant pressure of an ideal gas is (7/2) R. The ratio of specific heat at constant pressure to that at constant volume i...
A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased so as to increase its effic...
An ideal gas heat engine operates in Carnot cycle between 227oC and 127oC. It absorbs 6 $$\times$$ 104 cal of heat at higher temperature. Amount of ...
Which of the following processes is reversible?
The equation of state for 5 g of oxygen at a pressure P and temperature T, when occupying a volume V, will be (where R is the gas constant)
One mole of an ideal gas at an initial temperature of T K does 6R joule of work adiabatically. If the ratio of specific heats of this gas at constant ...
An ideal gas heat engine operates in a Carnot cycle between 227oC and 127oC. It absorbs 6 kcal at the height temperature. The amount of heat (in kcal)...
The efficiency of Carnot engine is 50% and temperature of sink is 500 K. If temperature of source is kept constant and its efficiency raised to 60%, t...
A scientist says that the efficiency of his heat engine which work at source temperature 127oC and sink temperature 27oC is 26%, then...
To find out degree of freedom, the expansion is
The (W/Q) of a Carnot engine is 1/6, now the temperature of sink is reduced by 62oC, then this ratio becomes twice, therefore the initial temperature ...
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