12. Thermodynamics

Figure shows a P–V diagram. The work done by the process AB is

• 900 J

• 1500 J

• 3300 J

• 33 J

Two moles of an ideal gas at 300 K were cooled at constant volume so that the pressure is reduced to half the initial value. Then, as a result of heating at constant pressure, the gas has expanded till it attains the original temperature. The total heat absorbed by gas, if R is the gas constant

• 150R

• 300R

• 75R

• 100R

Equal amount of same gas in two similar cylinders A and B, compressed to same final volume from same initial volume one adiabatically and another isothermally, respectively, then

• the final pressure in A is more than in B.

• the final pressure in B is greater than in A.

• the final pressure in both is equal.

Which of the following cannot determine the state of a thermodynamic system?

• Pressure and volume.

• Volume and temperature.

• Temperature and pressure.

• Any one of pressure, volume or temperature.

For free expansion of the gas which of the following is true?

• Q=W=0 and ΔU=0

• Q=0, W>0 and ΔU = -W

• W =0,Q>0, and ΔU =Q

• W>0,Q<0 and ΔU=0

In an isothermal process, the volume of an ideal gas is halved. One can say that the

• internal energy of the system decreases.

• work done by the gas is positive.

• work done by the gas is negative.

• internal energy of the system increases.

A cyclic process ABCD is shown in the figure P–V diagram. Which of the following curves represent the same process?

• 
• 
• 
• 

Starting with the same initial conditions, an ideal gas expands from volume V1 to V2 in three different ways: The work done by the gas is W1 if the process is purely isothermal, W2 if the process is purely isobaric, and W3 if the process is purely adiabatic, then

• W1>W2>W3

• W2>W3>W1

• W3>W2>W1

• W2>W1>W3

Which of the following is correct in terms of increasing work done for the same initial and final state?

• Adiabatic < Isothermal < Isobaric

• Isobaric < Adiabatic < Isothermal

• Adiabatic < Isobaric < Isothermal

• None of these

In a given process for an ideal gas, dW = 0 and dQ < 0. Then for the gas

• the temperature will decrease.

• the volume will increase.

• the pressure will remain constant.

• the temperature will increase.