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JEE Main20207 Jan 2020Morning ShiftPhysicsThermodynamicsActual

A litre of dry air at STP expands adiabatically to a volume of 3 litres. If γ = 1.40 , the work done by air is: 3 1.4 = 4.6555 [Take air to be an ideal gas]

Options

  1. A60.7 J
  2. B90.5 J
  3. C100.8 J
  4. D48 J

Correct answer

B. 90.5 J

Step-by-step solution

P 1 = 1 a t m , T 1 = 273 K P 1 V 1 γ = P 2 V 2 γ P 2 = P 1 V 1 V 2 γ = 1 a t m 1 3 1.4 Now work done = P 1 V 1 - P 2 V 2 γ - 1 = 90.5 J

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