Thermodynamics

Thermodynamics

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Thermal Physics

Thermal Properties of Matter
Thermodynamics
Kinetic Theory
  1. During an adiabatic process, the pressure of a gas is found to be proportional to the cube of
    its temperature. The ratio of
    Cp
    		for the gas is
    Cv








  1. View Hint View Answer Discuss in Forum

    According to question P ∝ T3
    ​But as we know for an adiabatic process the

    pressure P ∝
    γ
    Tγ - 1

    So ,
    γ
    		 = 3 ⇒ γ =
    3
    		 or,
    Cp
    		 =
    3
    γ - 12Cv2

    Correct Option: C

    According to question P ∝ T3
    ​But as we know for an adiabatic process the

    pressure P ∝
    γ
    Tγ - 1

    So ,
    γ
    		 = 3 ⇒ γ =
    3
    		 or,
    Cp
    		 =
    3
    γ - 12Cv2

  1. A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cyclic process is :​









  1. View Hint View Answer Discuss in Forum

    ∵ Internal energy is the state function.
    ​∴ ​In cyclie process; ∆U = 0 ​
    According to 1st law of thermodynamics​

    ∆Q = ∆U + W

    So heat absorbed ​
    ∆Q = W = Area under the curve ​
    = –  (2V) (P) = –  2PV ​
    So heat rejected = 2PV

    Correct Option: A

    ∵ Internal energy is the state function.
    ​∴ ​In cyclie process; ∆U = 0 ​
    According to 1st law of thermodynamics​

    ∆Q = ∆U + W

    So heat absorbed ​
    ∆Q = W = Area under the curve ​
    = –  (2V) (P) = –  2PV ​
    So heat rejected = 2PV

  1. Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning?​​








  1. View Hint View Answer Discuss in Forum

    Adiabatic equations of state are ​
    PVγ = constant ​
    TVγ–1 = constant
    ​P1–γTγ = constant.

    Correct Option: A

    Adiabatic equations of state are ​
    PVγ = constant ​
    TVγ–1 = constant
    ​P1–γTγ = constant.

  1. 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 and then its volume is reduced from 3V to V at constant pressure. The correct P-V diagram representing the two processes is :​








  1. View Hint View Answer Discuss in Forum

    1st process is isothermal expansion which is only correct shown in option (d)
    ​2nd process is isobaric compression which is correctly shown in option (d)

    Correct Option: D

    1st process is isothermal expansion which is only correct shown in option (d)
    ​2nd process is isobaric compression which is correctly shown in option (d)

  1. A gas is taken through the cycle ABCA, as shown in figure. What is the net work done by the gas ?









  1. View Hint View Answer Discuss in Forum

    Wnet = Area of triangle ABC

    =
    1
    		AC × BC
    2

    =
    1
    		 × 5 × 10-3 × 4 × 105 = 1000 J
    2

    Correct Option: A

    Wnet = Area of triangle ABC

    =
    1
    		AC × BC
    2

    =
    1
    		 × 5 × 10-3 × 4 × 105 = 1000 J
    2