作者Honor1984 (希望願望成真)
看板TransPhys
標題Re: [考古] 請問三題考古計算題
時間Tue Jul 8 18:07:24 2008
※ 引述《flygey (努力達成目標)》之銘言：
: 1.(a)A Carnot engine operates between a hot reservoir at 320K and a cold one
: at 260K. If the engine absorbs 500J as heat cycle at the hot reservoir,
: how much work per cycle does it deliver?
: (b)If the engine working in reverse functions as a refrigerator between the
: same two reservoirs,how much work per cycle must be supplied to remove
: 1000J as heat from the cold reservoir?
: 2.An electric dipole with dipole moment →p=(3.00i+4.00j)(1.24x10^-30 C‧m)
: is in an electric field →E=(4000 N/C)i
: (a)What is the potential energy of the electric dipole?
: (b)What is the torque acting on it ?
: (c)If an external agent turns the dipole until its electric dipole moment is
: →p=(-4.00i+3.00j)(1.24x10^-30 C‧m), how much work is done by the agen?
: 3.在溫度T很低的時候,許多固體的定容摩耳比熱Cv與溫度的關係可以近似為Cv=AT^3,
: 其中A與特定的材料有關,對鋁而言,A=3.15x10^-5 J/molx k^4.
: 求；4.00 mol 的鋁,溫度由5.00K上升到10.0K時,entropy(熵)的改變量.
S = 積分 nCv dT / T
= 積分nAT^2 dT
= (1/3)nA[(Tf)^3 - (Ti)^3]
= (1/3)*4*3.15x10^(-5) * [10^3 - 5^3] (J/k)
: 請版友幫解感謝
: 感謝幫忙
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