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Highly selective Backlog Qs for JEE MainChemistryThermodynamics (C)

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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