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GATE 2026 ME – Question 23

Thermodynamics · Ideal and real gases · 1 mark · Multiple choice

For an ideal gas, starting from state point 1, two different processes take place. The corresponding final states in these two processes are 2 and 3, lying on same isotherm. If $P$ and $h$ represent pressure and enthalpy, respectively, then which one of the following options is correct?

  1. $h_2 = h_3$
  2. $h_2 > h_3$
  3. $P_2h_3 = P_3h_2$
  4. $P_3h_3 = P_2h_2$

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Show answer and explanation

Correct answer: (A) $h_2 = h_3$

Explanation

For an ideal gas the enthalpy depends only on temperature, $h = c_pT$. States 2 and 3 are on the same isotherm, so they have the same temperature and the same enthalpy.