本區搜索:
Yahoo!字典
打印

[Phy] URGENT!!! electric circuit 兩問

[隱藏]

URGENT!!! electric circuit 兩問

1
an ammeter is inserted at X, find the redaing of the ammeter if its internal resistance is
(i) 10 ohm
(ii) 1 ohm

2.
a) find the voltage across the 80 ohm resistor
b) a voltmeter is connected across X and Y to measure the potential difference acorss the 80 ohm resistor. Find the reading of the voltmeter if its internal resistance is
(i) 50 ohm
(ii) 50 k ohm
附件: 您所在的用戶組無法下載或查看附件
   
2012 AL
CL&C   UE   MS   PHY   BIO

TOP

1.
if its internal resistance is 10 ohm
total resistance of the circuit = 10+16+8 ohm = 34 ohm
V=IR
12=I(34)
I=0.353A

if its internal resistance is 1 ohm
total resistance of the circuit = 1+16+8 ohm = 25 ohm
V=IR
12=I(25)
I=0.48A

2.
Current of the circuit = 12/240 =0.05A
Voltage across the 80ohm resistor = 0.05x80=4V

If the internal resistance of the voltmeter is 50 ohm
Equivalent resistance of the 80ohm resistor and voltmeter = 1/(1/50 + 1/80)=400/13 ohm
Voltage measured = 12x(400/13)/(160+400/13)=1.94V

If the internal resistance of the voltmeter is 50k ohm
Equivalent resistance of the 80ohm resistor and voltmeter = 1/(1/50 000 + 1/80)=25000/313ohm
Voltage measured = 12x(25000/313)/(160+25000/313)=4.00V

有錯請指
2012 AL
AL Physics + AL Chemistry + AL Biology + AL Pure + CLC + UE

TOP

回覆 #2 abchh 的帖子

個答案岩ar...不過我想知咩叫"equivalent resistance", 加左個equivalent 有咩分別??
2012 AL
CL&C   UE   MS   PHY   BIO

TOP

等效電阻, 亦即是 total resistance on the circuit.

TOP

明哂, thz 兩位ching
2012 AL
CL&C   UE   MS   PHY   BIO

TOP

重要聲明:小卒資訊論壇 是一個公開的學術交流及分享平台。 論壇內所有檔案及內容 都只可作學術交流之用,絕不能用商業用途。 所有會員均須對自己所發表的言論而引起的法律責任負責(包括上傳檔案或連結), 本壇並不擔保該等資料之準確性及可靠性,且概不會就因有關資料之任何不確或遺漏而引致之任何損失或 損害承擔任何責任(不論是否與侵權行為、訂立契約或其他方面有關 ) 。