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MHT CET 2021 (24 Sep, Shift 2) · Specific Heats of Gases - Cp, Cv, γ & Mayer's Relation

Specific Heats of Gases - Cp, Cv, γ & Mayer's Relation question from MHT CET 2021 (24 Sep, Shift 2)

Q35MHT CET 2021 · 24 SEP · SHIFT 2Easy

Specific Heats of Gases - Cp, Cv, γ & Mayer's Relation

Which one of the following is NOT a correct expression for an ideal gas?

[Cp=C_p = Molar specific heat of a gas at constant pressure,

Cv=C_v = Molar specific heat of a gas at constant volume,

γ=\gamma = Ratio of two specific heats of a gas,

R=R = Universal gas constant]

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Answer: (a)

  1. Mayer: Cp−Cv=RC_p - C_v = R, so Cv=Cp−RC_v = C_p - R, not Cp+RC_p + R. (a) is wrong.
  2. (b) R=Cp−Cv=Cv(γ−1)R = C_p - C_v = C_v(\gamma - 1): correct.
  3. (c) CvCp=1γ\frac{C_v}{C_p} = \frac{1}{\gamma}: correct by definition.
  4. (d) R=Cp−Cpγ=Cp(γ−1)γR = C_p - \frac{C_p}{\gamma} = \frac{C_p(\gamma-1)}{\gamma}: correct.
  5. So the answer is (a).
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