For an ideal gas the adiabatic equation linking pressure and volume is:
AP V = constant
BP V^γ = constant
CP / V = constant
DP V² = constant
Answer & Solution
Correct answer: B. P V^γ = constant
1. For an adiabatic (Q = 0) reversible process on an ideal gas, dU = −PdV.
2. Using dU = n Cv dT and the ideal gas law leads to PV^γ = constant.
3. The exponent γ = Cp/Cv > 1, so adiabats are STEEPER than isotherms (PV = const) on a P–V diagram.
4. Equivalent forms: T V^(γ−1) = const, T^γ P^(1−γ) = const.
_Source: NCERT Class 11 Physics Ch 11, §11.7 Adiabatic Process_
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