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In the arrangement shown in figure. Gas is thermally insulated. An ideal gas is filled in the cylinder having pressure P0 (> atmospheric pressure Pa). Spring of force constant k is initially unstretched. Piston of mass m and area S is frictionless. In equilibrium piston rises up a distance x0, then
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Important Questions on Thermodynamics

EASY
Which of the following statement is incorrect
HARD
A one mole of ideal gas goes through a process in which pressure P varies with volume V as P=3-gVV02, where V0 is a constant. The maximum attainable temperature by the ideal gas during this process is (All quantities are in SI units and R is gas constant)
EASY

Consider the following thermodynamical variables
(i) Pressure
(ii) Internal Energy
(iii) Volume
(iv) Temperature

Out of these, the intensive variable(s) is (are)

EASY
A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then:
HARD
A closed tank has two compartments A and B, both filled with oxygen (assumed to be ideal gas). The partition separating the two compartments is fixed and is a perfect heat insulator (Figure1). If the old partition is replaced by a new partition which can slide and conduct heat but does not allow the gas to leak across (Figure 2), the volume (in m3) of the compartment A after the system attains equilibrium is 20x m3. Write the value of x.

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HARD
Consider a spherical shell of radius R at temperature T. The black body radiation inside it can be considered as an ideal gas of photons with internal energy per unit volume u=UVT4 and pressure p=13UV . If the shell now undergoes an adiabatic expansion the relation between T and R is:
EASY

Consider the given diagram. An ideal gas is contained in a chamber (left) of volume V and is at an absolute temperature T. It is allowed to rush freely into the right chamber of volume V which is initially vacuum. The whole system is thermally isolated. What will be the final temperature, if the equilibrium has been attained?

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MEDIUM
One mole of an ideal monatomic gas undergoes an adiabatic expansion in which its volume becomes eight times its initial value. If the initial temperature of the gas is 100K and the universal gas constant R=8.0 J mol-1 K-1, then how much is the decrease in its internal energy (in J) ?
EASY

The pressure versus temperature graph of an ideal gas is shown in the figure below. If the density of gas at point A is ρ0, then the density of the gas at point B will be

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MEDIUM

A system goes from A to B via two processes I and II shown in the figure. If ΔU1 and ΔU2 are the changes in internal energies in the processes I and Il respectively

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HARD
A gas is enclosed in a cylinder with a movable frictionless piston. Its initial thermodynamic state at pressure Pi=105 Pa and volume Vi=10-3 m3 changes to a final state at Pf=132×105 Pa and Vf=8×10-3 m3 in an adiabatic quasi-static process, such that P3V5= constant. Consider another thermodynamic process that brings the system from the same initial state to the same final state in two steps: an isobaric expansion at Pi followed by an isochoric (isovolumetric) process at volumes Vf . The amount of heat supplied to the system in the two step process is approximately
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Three different processes that can occur in an ideal monoatomic gas are shown in the P vs V diagram. The paths are labelled as AB,AC and AD. The change in internal energies during these process are taken as EAB,EAC and EAD and the work done as WAB,WAC and WAD. The correct relation between these parameters are:

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EASY
Half mole of an ideal monoatomic gas is heated at a constant pressure of 1atm from 20° C to 90° C. Work done by the gas is(Gas constant,R=8.21 J mol-1 K-1)
EASY
If system A is in thermal equilibrium with B and B is separately in thermal equilibrium with C, then A and C are in thermal equilibrium. From which thermodynamics law, does this follow?
EASY

For the given cyclic process CAB as shown for a gas, the work done is:

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The above P-V diagram represents the thermodynamic cycle of an engine, operating with an ideal mono-atomic gas. The amount of heat, extracted from the source in a single cycle, is:
HARD
One mole of a monatomic ideal gas undergoes a cyclic process as shown in the figure (where V is the volume and T is the temperature). Which of the statements below is (are) true?

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EASY

Pressure versus temperature graph of an ideal gas at constant volume V is shown by the straight-line A. Now mass of the gas is doubled and the volume is halved then the corresponding pressure versus temperature graph will be shown by the line

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EASY
A balloon is filled at 27 °C and 1 atm pressure by 500 m3 He. At -3 °C and 0.5 atm pressure, the volume of He will be
MEDIUM
n moles of an ideal gas undergoes a process AB as shown in the figure. The maximum temperature of the gas during the process will be:
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