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JEE Main 2021 (18 Mar, Shift 2) · Thermodynamic Processes

Thermodynamic Processes question from JEE Main 2021 (18 Mar, Shift 2)

Q191JEE Main 2021 · 18 MAR · SHIFT 2Medium

Thermodynamic Processes

For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where γ\gamma is the ratio of specific heats):

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Answer: (c)

  1. PVγ=PV^{\gamma} = const. Take logs: ln⁡P+γln⁡V=\ln P + \gamma \ln V = const.
  2. Differentiate: dPP+γdVV=0\frac{dP}{P} + \gamma\frac{dV}{V} = 0
  3. So the answer is (c) dPP=−γdVV\frac{dP}{P} = -\gamma\frac{dV}{V}.
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