A thermally insulated vessel contains an ideal gas of molecular mass M and ratio of specific heats 1 . 4 .…

A thermally insulated vessel contains an ideal gas of molecular mass M and ratio of specific heats 1.4. Vessel is moving with speed v and is suddenly brought to rest. Assuming no heat is lost to the surrounding and vessel temperature of the gas increases by :
(R= universal gas constant)
  1. Mv27R
  2. Mv25R
  3. 2Mv27R
  4. 7Mv25R

Solution

KE of the vessel =12mv2

When the vessel is suddenly stopped, the ordered motion of the gas molecules is converted into disordered motion of the molecules increasing thereby the internal energy of the gas. Thus,

U=nCvT=12mv2=12nMv2

Where n is number of moles of the gas in the vessel and M is molecular weight of the gas.

  T=Mv22Cv

As Cv=Rγ-1

  T=Mv2(γ-1)2R=Mv2(1.4-1)2R=Mv25R

Asked in: JEE Main 2022 (26 Jun Shift 1)

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