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QJEEAdv18Ph2919: JEE Advanced 2018 Physics - Class 11 JEEAdv18Ph2919 Solution: One mole of a monatomic ideal gas undergoes a cyclic process as …

One mole of a monatomic ideal gas undergoes a cyclic process as shown in the figure (where VV is the volume and TT is the temperature). Which of the statements below is (are) true?

JEE Advanced 2018 Paper 1 Offline Physics - Heat and Thermodynamics Question 51 English

Multiple Choice Options

  • A Process I{\rm I} is an isochoric process
  • B In process II{\rm II} , gas absorbs heat
  • C In process IV{\rm IV} , gas releases heat
  • D Process I{\rm I} and III{\rm III} are not isobaric

Step-by-Step Verified Solution

In process I, volume is changing. Therefore, it is not isochoric. Therefore 'A' is incorrect.

In process II, q = Δ\Delta U + W . Δ\Delta U = 0 as temperature is constant. Therefore, q = W. Here W = P(Vf −- Vi) is positive therefore q is positive i.e., gas absorbs heat. Therefore 'B' is correct.

For process IV, q = Δ\Delta U + W. Here Δ\Delta = 0 and W is negative (volume decreases). Therefore q is negative i.e., gas releases heat. 'C' is correct.

For an isobaric process, V ∝\propto T i.e., we will get a straight inclined line in T-V graph. Therefore I and II are NOT isobaric. 'D' is correct.

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