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MHT CET202410 May 2024Evening ShiftChemistryThermodynamics (C)Actual

A gas expands isothermally against a constant external pressure of 1 bar from 10 dm ^3 to 20 dm ^3 by absorbing 800 J of heat from surrounding. Calculate value of U .

Options

  1. A100 J
  2. B-200 ~J
  3. C200 J
  4. D-300 J

Correct answer

B. -200 ~J

Step-by-step solution

aligned & P _ ext =1 bar & V ₁=10 dm ^3, ~V ₂=20 dm ^3 & Q =800 ~J & ~W =- P _ ext ( V ₂- V ₁ )=-1 bar (20 dm ^3-10 dm ^3 ) & =-10 dm ^3 bar =-1000 ~J & U = Q + W =800 ~J -1000 ~J =-200 ~J aligned

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