作者sleepinggod (別再幻想了)
看板Gov_owned
標題Re: [討論] 電機乙第四題討論
時間Wed Dec 31 22:53:15 2014
寄出釋疑申請書後才找到這書 可惜好像不是正式的課本
有板友願意把這本書寫的寫進釋疑申請書嗎?
electric flux 算出來的單位是 庫倫
算式應該用 D ds 的積分
http://pokhara.academia.edu/AshokChhetry
http://ppt.cc/Wgv1
Faraday's experiments also showed, of course, that a larger positive charge
on the inner sphere induced a correspondingly larger negative charge
on the outer sphere, leading to a direct proportionality between the
electric flux and the charge on the inner sphere. The constant of
proportionality is dependent on the system of units involved, and we are
fortunate in our use of SI units, because the constant is unity. If electric
flux is denoted by Φ (psi) and the total charge on the inner sphere by Q,
then for Faraday's experiment
Φ = Q
and the electric flux Φ is measured in coulombs.
另一書本也是用這種的定義
《ELECTROMAGNETIC WAVES AND RADIATING SYSTEMS》Second Edition│Edward Conrad
Jordan, Keith George Balmain
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※ 編輯: sleepinggod (36.226.146.21), 12/31/2014 22:56:39
1F：→ ln123: 請把高斯大師的定理看仔細，不要拿其他文章申請疑義 12/31 23:01
在不同的單位系統 會有不同的寫法
例如在 CGS Lorentz-Heaviside units. Electric flux = Q
Take a look at CGS Lorentz-Heaviside units. You will notice that the units
have been chosen such that the flux, calculated using the electric field, is
equal to the enclosed charge. There are some slightly different ways of
working with Maxwell's equations. Sometimes people like to formulate them so
that the inherent physics stands out without much distraction. Like the
Lorentz-Heaviside units, it is easier to work with flux equal to charge than
flux being equal to charge times some weird number. I prefer MKS myself
because then there is no conversion between SI units, which are usually used
for measurement, and the results of the equations.
https://www.physicsforums.com/threads/the-unit-of-flux-density.334061/
在相同的討論串中也有人提到
著名的 CRC Handbook 也是用 D.ds的積分
In the CRC Handbook, they defined the electric flux to be the integral of the
electric flux density, not the electric field, and so that relationship would
still be correct.
我找不到Gauss 的原始論文, 搞不好他是用εE.ds 的面積分 = Q,
在均勻介質中可以把 ε搬出積分然後移到等號右邊,
才會變成 E.ds的面積分 = Q/ε 這只是特例(在均勻介質中)
※ 編輯: sleepinggod (36.226.146.21), 12/31/2014 23:27:04
※ 編輯: sleepinggod (36.226.146.21), 01/01/2015 00:47:32
※ 編輯: sleepinggod (36.226.146.21), 01/01/2015 00:54:33
※ 編輯: sleepinggod (36.226.146.21), 01/01/2015 00:55:14
※ 編輯: sleepinggod (36.226.146.21), 01/01/2015 01:00:54
2F：→ ln123: 你可以把當年高斯提出電通量一辭的論文找出來？看他當年是 01/01 01:02
3F：→ ln123: 定義EA還是DA？ 01/01 01:02
※ 編輯: sleepinggod (36.226.146.21), 01/01/2015 01:33:32
4F：→ sleepinggod: l大 如果你有高斯的論文 可以分享嗎? 01/01 01:34