請問P=F/A為什麼會正比於I^2/R^2 ?? 而不是I^2/R^3??

詳解 1. 設中空圓筒形導體長為L,依題意可知: I,n> ½‚n » 1, P = , Ò與È同方向 A 2元R×L n F Px R R (A)(B)兩載同向電流的直導線間有相互吸引的磁力 Hoi F'=iL × B, B = 其中rxR。如下示 2лг 意圖所示,利用向量對稱分析可得任一導線 所受的淨磁力會指向圓心O,即Ò沿半徑向 筒內。 i dat 21 O (C)(D)(E) Foc | iLẺ | F > P = x A I² R² 8 R 8 T² R i

Grant argues that people should act like scientists, experimenting, considering all possible explanations and questioning earlier beliefs... 繼續閱讀

想問問，20題為什麼不是A for加一段時間不是完成式嗎？🤔

D b 18. Business at Jane's shop has not been good these days/And the new supermarket across the street only makes things worse. (A) easier (B) worse 使現況更糟 Qm more boring (D) more convenient pulled him out of a car on fire. (C) the one she (D) the one who 19. Scott wasn't sure if the young woman before him was 20. I (A) who (B) the one swimming for several years before I went to this high school I gave it up because of heavy schoolwork. (A) have practiced (B) am practicing (C) practiced 21. Frank Kane is so good in the movie that many people 22. (A) expect (B) forget (D) would practice he will win the best actor prize (C) notice (D) plan thousands of lives. (C) saving (D) to save The new medicine that just came out on the market (A) and saved (B) has saved

As a class leader, you might think you are expected to do everything well. But in fact,you don't need to push yourself that hard.的expecte... 繼續閱讀

想請問這題，是清大先修課（微積分）的題目！ 有點看不太懂詳解⋯⋯ 非常感謝！><

微積分 w1 ex02-01q3 (單選題) Let f (x) = 2x, c = 1, = 0.1, L = 2, pick up an appropriate positive number 8 from the following options such that if 0 < |x − 1| < 8, then |f(x) − L| = |2x − 2| < € = 0.1. ○ 8 = 4 O 8 = 0.049 8= 0.051 8 = 0.1 解答: "8=0.049 " 詳解: Observe that | 2x-21 = 2|x1| < 0.1 = >> |x1|< 0.1 = 0.05. 2 Hence for &= 0.1, we can take any positive number 8≤ 0.05, such that if 0 < |x − 1| < 8, then |f(x) – L| = |2x-2| 2x 128≤ 2 0.05 = 0.1 = ε.

為什麼B相對高溫又是好天氣 解答說的

(C)地表輻射冷卻導致空氣溫度改變 (E)空氣塊過山後產生落山風〔113 學測〕 二、(A)氣流受到地形抬升,沿著迎風坡爬升(B) 暖空氣吹過冷海面 (D)空氣在地面高壓區的上空向下沉 屆試題 (E)線香在此實驗中扮演「凝結核」的角色 )(20若空氣中水氣含量不變,下列哪些方式最不可能發生水氣凝結現象?(應選2項) 氣溫 021.北半球有一溫帶氣旋,其地面氣壓與鋒面的分布如附圖所示。 下列有關此天氣圖的敘述,何者正確? (A)甲地點大約吹西風 (B)乙地點的溫度最低 (C)丙地點的氣壓最高ON(D)工地點大約吹西北風↓ (E)乙地點的天氣是陰雨天〔113 學測〕 戊 丁 丙 )22. 一個未飽和空氣塊在上升過程中,假設不與環境交換熱量,每上升1公里,溫度約降 低10℃:露點每上升1公里約降低2°C。假設有五個地點,在高度為0時,其溫度和 露點如附表。若各自的空氣塊上升至附圖高度時,哪些地點較可能開始形成雲層的雲 底?(應選2項) 3 地點 溫度(℃) 18 甲 乙 丙 丁 戊 22 26 30 34 露點(°C) 12 14 18 18 14 N 2 高度(公里

為什麼這題選B不能選A

The man (she met at the conference is a famous writer. A. who B. whom C. which D. whose

求解

8. Lisa: Dad, we have to go to church tomorrow, ? Dad: Yes, tomorrow is Saturday. After that, let's go to a movie. A) haven't we (C) won't we have to (B) aren't we (D) don't we

求解

牙 9. Everyone was talking about Jasmine at the party last night because she dressed than all the other girls. 2m() (A) beautiful 20 om nogoo of og of tow llite 1 di biofle 'n I (B) more beautiful 11(A) (C) more beautifully (D) the most beautifully 192010 (A)

這題為什麼選B

7. It has not rained for weeks. The weather report says that there may (B) tomorrow. (A) rainbow (C) be rainy (B) be rain (A) EA (D) have rain (8) zi gnidouot lls jon ()