Originally posted by Rookierookie at 2006-3-26 23:17:
該點上 electron 所帶的能量
Originally posted by [S]【YU】 at 2006-3-27 11:27:
電路接地後=short circuit=電流會無限增加,直到燒fuse
Originally posted by Rookierookie at 2006-3-27 16:43:
短路
7. V = IR
R constant
V increase
Therefore I decrease
好似係咁...不過可能錯 (看見上面的回覆)
8. *估*
可能因為 electricity takes the path of least resistance
如果用導電液體/parti ...
Originally posted by 博士.Dota at 2006-3-26 23:13:
Q6. 電路接地後,電流會減少嗎?
┌───│| ────┐
│ │
└──〔接地〕───┘
A B
電流仍會由 A 到 B 嗎?
那麼接地有什麼影響?為什麼?
Originally posted by 博士.Dota at 2006-3-26 23:13:
Q6. 電路接地後,電流會減少嗎?
┌───│| ────┐
│ │
└──〔接地〕───┘
A B
電流仍會由 A 到 B 嗎?
那麼接地有什麼影響?為什麼?
Q7. 當流過人體的電壓增加時,人體電阻會下降?
Q8.在展示電場圖形的實驗(Demostration of electric field pattern around electrodes)中,為什麼要使用不導電(non-conducting) 的液體及粉狀物(Powder) ?
Originally posted by AtMa at 2006-3-27 18:47:
你收皮吧=︵=”
as the positive charges move close to one side of the earthed conductor,potential at that ...
Originally posted by albie at 2006-3-27 18:53:
8. 因為如果佢用左conducting material ge話
個circuit變左complete,
所以冇electric field produced
Originally posted by [S]【YU】 at 2006-3-28 00:32:
Q3 , 一個conducting sphere 本身有 equal amount of +ve and -ve charges.
uniformly distributed --> neutral
+ve charged rod 放近, 負既吸埋來,正既彈開去
因為佢地分開左,set up 既 electric field 剛剛抵銷左charged rod的electric field.
所以應該無potential difference.
Originally posted by [S]【YU】 at 2006-3-28 00:32:
complete circuit 唔係無electric field.
應該話,non-resistance components of a complete circuit have no electric field.
Originally posted by [S]【YU】 at 2006-3-28 00:32:
6. 係呢度接地係冇用的,
由於個circuit本身係short左,
所以所有電流都會行個circuit,
可況,佢即使係earth左,
佢冇provide一個return path,所以earth係度係冇用的
Originally posted by [S]【YU】 at 2006-3-28 00:32:
7. resistance係independent to voltage or current.
Originally posted by [S]【YU】 at 2006-3-28 00:32:
可況呢句 "流過人體的電壓增加",呢句有問題
Originally posted by albie at 2006-3-27 18:53:
6. 係呢度接地係冇用的,
由於個circuit本身係short左,
所以所有電流都會行個circuit,
可況,佢即使係earth左,
佢冇provide一個return path,所以earth係度係冇用的
Originally posted by 博士.Dota at 2006-3-28 06:53:
咁係唔係假如係 B 放個燈泡,個燈泡唔會著?
第 7 題加o左問題係上面...
我同意 "resistance係independent to voltage or current."
係唔係答案出錯?
有無 return path 有咩影響?
唔係就算無 return path, 電流都會不停流向地球嗎?
Q9. 電流由 高電勢 的地方流向 低電勢 的地方嗎?
Originally posted by albie at 2006-3-28 10:55:
當然會la,話明全部電流都會係條電線上流動,
既然而家有電流,當然會著la!!
Originally posted by Rookierookie at 2006-3-28 13:20:
不明白怎樣會扯上了 E.M.F. 的
Originally posted by Rookierookie at 2006-3-28 13:29:
首先 e.m.f stands for what?
Originally posted by [S]【YU】 at 2006-3-28 13:55:
potential 呢家野真係好煩.
一個+ve charged sphere 的potential 是+ve , electric field 指出
一個-ve charged sphere 的 potential 是-ve , electric field 指入
earth 的 potential 是 0
電池兩邊無分正 ...
Originally posted by 博士.Dota at 2006-3-28 13:10:
燈泡兩端 o既電壓差 係唔係 電池 e.m.f?
接o左地 唔係 0 電勢咩???
(根據上面 o既答案諗的...)
[ Last edited by 博士.Dota on 2006-3-28 at 01:13 PM ]
Originally posted by 博士.Dota at 2006-3-28 13:57:
咁電勢差 o既大小 又代表什麼?
我要 Off... 下午先睇番
[ Last edited by 博士.Dota on 2006-3-28 at 01:59 PM ]
Originally posted by albie at 2006-3-28 14:04:
電勢差=舊電池ge voltage...
Originally posted by albie at 2006-3-28 14:04:
其實你係唔係搞錯左earthing 同earth wire,
呢個係electric circuit,係冇所為ge earth wire
而earthing亦都係for electrostatic,
其實earht ge resistance係幾大下ga,
如果一舊電池駁左去地,
由於R ...
Originally posted by 博士.Dota at 2006-3-28 18:02:
我睇番條題目... 佢應該指 earthing...
電路中間o個度駁住個咁o既符號:
|
----------------
-------
好似越講越遠添...番番去個問題
即係假如咁樣接地...仍有電流由A 向 B...電壓亦無影響,
電流不會流到地球, 因為短路, 同條地線無return path?
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