伊莉討論區

標題: 請電路學達人解答~ [打印本頁]

作者: qqasdasd52 時間: 2010-10-31 02:45 PM 標題: 請電路學達人解答~

一序述.水和電的相同性跟差異性?

二.兩相距6公分之電荷.其帶電量分別為Q及4Q在其連線上置一電子，若其所受之總力為零試問電子要置於何處??

三.ａ.ｂ兩導體，由同樣材料製成，ａ之長度為ｂ之２倍；ｂ的直徑為ａ的兩倍，若ａ導體之電阻為10Ω則ｂ導體之電阻若干??

四.何謂電阻係數？何謂溫度電阻係數？？

五.一實際電源接上５Ω之負載電阻時，其端電壓，為１０ｖ，若將５Ω之負載電阻改換為２Ω時，則其端電壓為６ｖ，求該電源之內阻若干Ω？？

幫~~計算題要寫出計算過程><"感恩...................

作者: avontube 時間: 2010-10-31 11:51 PM

本帖最後由 avontube 於 2010-11-22 01:53 AM 編輯

Q1 and Q2 are not circuit theory.  I will pass.
Q3: R is proportional to L/A where L is the length and A is the cross section area.
So, Ra : Rb = 2 : 0.25  Therefore, Rb = 1.25 Ohms

Q4: resistivity is opposite of conductivity.  The conductivity is on the amount of electrons (or charged carriers) and their mobility to flow through a cross-section.
In general, conductivity = n*q*u where n is the charge carrier density, q is the unit charge (1.6 * 10^-19) and u is the mobility.

However, the mobility is a function of the temperature.  Therefore, when temperature changes, the mobility changes.  And, at the same time, conductivity changes, and so does the resistivity.

Q5. V = 10 + 2R  (for case 1)  and V = 6 + 3R (for case 2).  Solve R, R = 4 Ohms.

QED

作者: vison680713 時間: 2010-11-21 05:05 PM

第三題
ａ之長度為ｂ之２倍則b=0.5a ｂ的直徑為ａ的兩倍則b面積=4a b=(0.5/4)*10=1.25Ohms

歡迎光臨伊莉討論區 (http://a401.file-static.com/)