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JEE Main2017ChemistryThermodynamics (C)Actual

A gas undergoes change from state A to state B . In this process, the heat absorbed and work done by the gas is 5 J and 8 J , respectively. Now gas is brought back to A by another process during which 3 J of heat is evolved. In this reverse process of B to A .

Options

  1. A6   J   of the work will be done by the gas
  2. B6   J of the work will be done by the surroundings on gas
  3. C10   J of the work will be done by the surroundings on gas
  4. D10   J of the work will be done by the gas

Correct answer

B. 6   J of the work will be done by the surroundings on gas

Step-by-step solution

for   A   to   B q = 5 W =   − 8   J , ΔU AB = dq + dw = 5 − 8 ΔU AB = − 3 for   B   to   A ΔU BA = dq + dw ΔU BA =   + 3 3 = - 3   + W BA               W BA = 6   J

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