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IAT IISER2026ChemistryThermodynamics (C)

An ideal gas goes through a reversible isothermal expansion (solid line) followed by a reversible adiabatic expansion (dashed line). Which of the following diagram(s) closely depict(s) the entire process?

Options

  1. A(ii) and (iv) only
  2. B(i) only
  3. C(i), (ii), and (iii) only
  4. D(i) and (iii) only

Correct answer

D. (i) and (iii) only

Step-by-step solution

Let us analyze the two processes given in the problem: 1. Reversible isothermal expansion (solid line): Temperature T remains constant. As the gas expands, volume V increases and pressure P decreases. Equation: PV = constant or P 1 V . 2. Reversible adiabatic expansion (dashed line): No heat is exchanged ( q = 0 ). As the gas expands, it does work at the expense of its internal energy, so temperature T decreases. Volume V increases and pressure P decreases. Equation: PV^ = constant and T^ P^ 1- = constant . Now, le

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