Thermodynamics PYQs Set 12 (PDF)

Set 12 of 16 · Questions 331-360 of 459

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Mere Teacher · Previous Year Questions NEET Physics · Thermodynamics · Set 12 (Q331-360)
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331. $A quantity of monoatomic gas undergoes a process in which pressure is changed linearly with volume. The pressure and volume are changed from initial value (P_{0}, V_{0}) to final value (3 P_{0}, 3 V_{0}) . The heat absorbed by the gas during process is$ (1) $8 P_{0} V_{0}$ (2) $12 P_{0} V_{0}$ (3) $16 P_{0} V_{0}$ (4) $20 P_{0} V_{0}$ 332. $A system goes from A and B via two processes I and II as shown in figure. If Δ U_{1} and Δ U_{2} are the ρ changes in internal energies in the processes I and II respectively, then the relation between Δ U_{1} and Δ U_{2} is$ (1) $Δ U_{1} = Δ U_{2}$ (2) $Δ U_{2} < Δ U_{1}$ (3) $Δ U_{2} > Δ U_{1}$ (4) $undetermined$ 333. $One mole of an ideal gas is taken from A to B, from B to C and then back to A . The variation of its volume with temperature for that change is as shown. Its pressure at A is P_{0}, volume is V_{0} . Then, the internal energy$ (1) $at A is more than at B$ (2) $at C is less than at B$ (3) $at B is more than at A$ (4) $at A and B are equal$ 334. $A graph of pressure versus volume for an ideal gas for different processes is as shown. In the graph curve OC represents$ (1) $isochoric process$ (2) $isothermal process$ (3) $isobaric process$ (4) $adiabatic process.$ 335. $A real gas within a closed chamber at 27^{\circ} C undergoes the cyclic process as shown in figure. The gas obeys P V^{3} = RT equation for the path A to B . The net work done in the complete cycle is (assuming R = 8 J / molK) :$ (1) $20 J$ (2) $205 J$ (3) $-20 J$ (4) $225 J$ 336. $Three different processes that can occur in an ideal monoatomic gas are shown in the P vs V diagram. The paths are labelled as A \to B, A \to C and A \to D The change in internal energies during these process are taken as E_{AB}, E_{AC} and E_{AD} and the work done as W_{AB} W_{AC} and W_{AD} The correct relation between these parameters are$ (1) $E_{AB} < E_{AC} < E_{AD}, W_{AB} > 0, W_{AC} > W_{AD}$ (2) $E_{AB} = E_{AC} = E_{AD}, W_{AB} > 0, W_{AC} = 0, W_{AD} > 0$ (3) $E_{AB} > E_{AC} > E_{AD}, W_{AB} < W_{AC} < W_{AD}$ (4) $None of These$ 337. $An ideal gas goes from state A to state B via three different processes as indicated in the P‐V diagram. If Q_{1}, Q_{2}, Q_{3} indicate the heat absorbed by the gas along the three processes and Δ U_{1}, Δ U_{2}, Δ U_{3} indicate the change in internal energy along the three processes respectively, then$ (1) $Q_{1} > Q_{2} > Q_{3} and Δ U_{1} = Δ U_{2} = Δ U_{3}$ (2) $Q_{3} > Q_{2} > Q_{1} and Δ u_{1} = Δ u_{2} = Δ u_{3}$ (3) $Q_{1} = Q_{2} = Q_{3} and Δ u_{1} > Δ u_{2} > Δ u_{3}$ (4) $Q_{3} > Q_{2} > Q_{1} and Δ u_{1} > Δ u_{2} > Δ u_{3}$ 338. $A thermodynamic system is taken through cyclic process. The total work done in the process is:$ (1) $200 J$ (2) $300 J$ (3) $100 J$ (4) $Zero$ 339. $In 1^{s t} case, Carnot engine operates between temperatures 300 K and 100 K. In 2^{n d} case, as shown in the figure, a combination of two engines is used. The efficiency of this combination (in 2^{n d} case) will be:$ (1) $same as the 1^{s t} case$ (2) $always greater than the 1^{s t} case$ (3) $always less than the 1^{s t} case$ (4) $may increase or decrease with respect to the 1^{s t} case$ 340. $A gas is compressed isothermally to half of its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then, [NEET 2016]$ (1) $compressing the gas through adiabatic process will require more work to be done.$ (2) $compressing the gas isothermally or adiabatically will require the same amount of work.$ (3) $which of the case (whether compression through isothermal or through adiabatic process) requires more work will depend upon the atomicity of the gas.$ (4) $compressing the gas isothermally will require more work to be done.$ 341. $The volume (V) of a monoatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas to the heat absorbed by it when it undergoes a change from state A to state B is [NEET 2018]$ (1) $\frac{1}{3}$ (2) $\frac{2}{3}$ (3) $\frac{2}{5}$ (4) $\frac{2}{7}$ 342. $A bimetallic strip is made of aluminium and steel (α_{Al} > α_{steel}) . On heating, the strip will$ (1) $remain straight$ (2) $get twisted$ (3) $bend with aluminium on concave side$ (4) $bend with steel on concave side$ 343. $Using the given P - V diagram, the work done by an ideal gas along the path ABCD is:$ (1) $3 P_{0} V_{0}$ (2) $- 4 P_{0} V_{0}$ (3) $- 3 P_{0} V_{0}$ (4) $4 P_{0} V_{0}$ 344. $thermodynamic process is shown below on a P - V diagram for one mole of an ideal gas. If V_{2} = 2 V_{1} then theratio of temperature T_{2} / T_{1} is:$ (1) $\frac{1}{2}$ (2) $\frac{1}{2}$ (3) $2$ (4) $2$ 345. $A thermodynamic system is taken from an original state D to an intermediate state E by the linear process shown in the figure. Its volume is then reduced to the original volume from E to F by an isobaric process. The total work done by the gas from D to E to F will be$ (1) $-450J$ (2) $450J$ (3) $900J$ (4) $350J$ 346. $A heat engine employing a Carnot cycle with an efficiency of η = 10% is used as a refrigerating machine, the thermal reservoirs being the same. The refrigerating efficiency \in is$ (1) $12$ (2) $8$ (3) $\frac{1}{10}$ (4) $9$ 347. $The given figure represents two isobaric processes for the same mass of an ideal gas, then$ (1) $P_{2} \geq P_{1}$ (2) $P_{2} > P_{1}$ (3) $P_{1} = P_{2}$ (4) $P_{1} > P_{2}$ 348. $A Carnot engine working between 300 K and 600K has a work out put of 800 J per cycle. The amount of heat energy supplied to the engine from the source in each cycle is -$ (1) $800 J$ (2) $1600 J$ (3) $3500 J$ (4) $6400 J$ 349. $A sample of an ideal gas is taken through the cyclic process ABCA as shown in figure. It absorbs, 40 J of heat during the part AB, no heat during BC and rejects 60J of heat during CA. A work 50J is done on the gas during the part BC. The internal energy of the gas at A is 1560J. The work done by the gas during the part CA is:$ (1) $20J$ (2) $30J$ (3) $-30J$ (4) $-60 J$ 350. $For three low density gases A, B, C pressure versus temperature graphs are plotted while keeping them at constant volume, as shown in the figure. The temperature corresponding to the point 'K' is:$ (1) $-273°C$ (2) $-100°C$ (3) $-373°C$ (4) $-40°C$ 351. $Two Carnot engines A and B operate in series such that engine A absorbs heat at T_{1} and rejects heat to a sink at temperature T. Engine B absorbs half of the heat rejected by Engine and rejects heat to the sink at T_{3} . When work done in both the cases is equal, to value of T is:$ (1) $\frac{2}{3} T_{1} + \frac{3}{2} T_{3}$ (2) $\frac{1}{3} T_{1} + \frac{2}{3} T_{3}$ (3) $\frac{3}{2} T_{1} + \frac{1}{3} T_{3}$ (4) $\frac{2}{3} T_{1} + \frac{1}{3} T_{3}$ 352. $An ideal gas at pressure P_{0} - undergoes an isothermal expansion until its volume is 8.0 times its initial volume. The gas is slowly and adiabatically compressed back to its original volume. If the adiabatic constant of the gas is γ = 4/3, then the ratio of the average kinetic energy per molecule in this final state to that in the initial state is$ (1) $1.44$ (2) $1.68$ (3) $2.0$ (4) $1.2$ 353. $The p - V diagram for an ideal gas in a piston cylinder assembly undergoing a thermodynamic process is shown in the figure. The process is [NEET 2020]$ (1) $adiabatic$ (2) $isochoric$ (3) $isobaric$ (4) $isothermal$ 354. $An ideal gas undergoes four different processes from the same initial state as shown in the figure below. Those processes are adiabatic, isothermal, isobaric and isochoric. The curve which represents the adiabatic process among 1, 2, 3 and 4 is [NEET 2022]$ (1) $2$ (2) $3$ (3) $4$ (4) $1$ 355. $Consider a gas of triatomic molecules. The molecules are assumed to be triangular and made of massless rigid rods whose vertices are occupied by atoms. The internal energy of a mole of the gas at temperature T is$ (1) $3 RT$ (2) $\frac{9}{2} RT$ (3) $\frac{3}{2} RT$ (4) $\frac{5}{2} RT$ 356. $For a given mass of a gas at constant temperature, the volume and the pressure are V and P respectively. Then the slope of the graph drawn between log_{e} V on X -axis and log_{e} P on Y-axis is$ (1) $1$ (2) $-1$ (3) $Zero$ (4) $Infinity$ 357. $A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected$ (1) $2 PV$ (2) $4 PV$ (3) $12 PV$ (4) $PV$ 358. $In a steady state, the temperature at the end A and end B of a 20 cm long rod AB are 100^{\circ} C and 0^{\circ} C . The temperature of a point 9 cm from A is$ (1) $55^{\circ} C$ (2) $45^{\circ} C$ (3) $65^{\circ} C$ (4) $50^{\circ} C$ 359. $The heat absorbed by a system in going through the given cyclic process is :$ (1) $19.6 J$ (2) $61.6 J$ (3) $616 J$ (4) $431.2 J$ 360. $An ideal gas exists in a state with pressure P_{0}, volume V_{0} . It is isothermally expanded to 4 times of its initial volume (V_{0}), then isobarically compressed to its original volume. Finally the system is heated isochorically to bring it to its initial state. The amount of heat exchanged in this process is$ (1) $P_{0} V_{0} (ln 2 - 0.75)$ (2) $P_{0} V_{0} (2 ln 2 - 0.75)$ (3) $P_{0} V_{0} (2 ln 2 - 0.25)$ (4) $P_{0} V_{0} (ln 2 - 0.25)$