9. Consider the adiabatic free expansion of an ideal gas system. The initial volume, pressure, and temperature are Vᵢ, Pᵢ, and Tᵢ, respectively. The final volume, pressure, and temperature are Vf, Pf, and Tf, respectively. What is the change in entropy ΔS of the gas? (Assume N is the number of molecules and k_B is Boltzmann's constant.)
(A) ΔS = Nk_B ln(Vf/Vᵢ)
(B) ΔS = Nk_B ln(Pf/Pᵢ)
(C) ΔS = Nk_B ln(Tf/Tᵢ)
(D) ΔS = Nk_B (Pf/Pᵢ)
(E) ΔS = Nk_B (Tf/Tᵢ)
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統計: 尚無統計資料
統計: 尚無統計資料
詳解 (共 1 筆)
#7443623
所以看到理想氣體+絕熱自由膨脹
要想到Q=0、W=0
所以內能會等於0
內能等於0又可以知道溫度變化為0
然後根據理想氣體方程式
PV正比於T
所以T不變
然後看到膨脹
要想到Vf大於Vi
所以答案為A
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