作者Qmmm (割掉Q)
看板TransPhys
標題[電磁] 台大轉 類似題
時間Sat Apr 11 22:20:28 2009
[台大轉]
A slab of copper thickness b is placed into a parallel plate
capacitors as shown in figure below; it is exactly halfway
between the plates.
(a)What is the capacitance after the slab is introduced?
(b)If a charge Q is maintained on the plates,
find the ratio of the stored energy before to that after
the slab in inserted.
(c)What is the force on the slab due to the plates?
↙ ______________________
w ╱ plate ╱ ____
╱ ╱￣￣￣￣￣￣↗∕|
↗ ╱←__ L _ → ╱ copper w ∕ |
↑ | ￣￣╱￣￣￣∕￣￣￣￣ ↙ _∕ ∕
a | ╱ |￣￣￣￣￣￣￣￣￣￣￣￣ |b∕
| ╱← x →| _ |∕
↓ | ╱ ￣￣￣￣￣╱￣￣￣￣￣￣￣
￣￣￣￣￣￣￣￣￣￣￣￣
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◆ From: 58.115.138.169
※ 編輯: Qmmm 來自: 58.115.137.72 (04/12 14:19)
→ astrotails:台大真是 = =這給大二的學生還不見得會寫吧 04/13 02:14
推 Tashuko:我補習班講義上有這題耶~"~ 04/13 13:18
→ Qmmm:剛找一下 老吳講義也有@@ 04/13 14:06
→ Qmmm:to 1F (a)、(b)其實還好 (c)就真的比較難 04/13 22:36
推 astrotails:不好意思看錯題了，光看圖還以為是cheng後面的習題XD 04/14 14:03
推 SDUM:(c) F=-▽V 原文書有哦(⊙o⊙) 04/15 01:34
→ astrotails:F=-▽V @@? 請問V是指? 04/15 01:39
推 SDUM:打錯，是U 位能 04/15 01:55
→ Qmmm:XD 3q 04/15 11:32
→ astrotails:忽然想到一個問題，向量微積分大一會教嗎，不好意思 04/15 15:19
→ astrotails:離大一年代太久遠了~"~ 04/15 15:19
→ astrotails:像grad divergence crul之類的 04/15 15:20
→ fong1014:梯度至少在教多變數時會教,EX方向導數.算子的內外積 04/15 16:45
→ fong1014:可能要看科系,商管的可能比較不會教 04/15 16:46
→ astrotails:現在小大一真辛苦，印象中我到修電磁才開始學 04/15 19:43
推 IAMROGER:這題不是基本題嗎? 04/18 01:08