kirchhoff rules

2007-06-10 6:07 pm
1.A single battery is connected to three resistors,as shown in Fig . 28 . 44 . Find the current in each resistor .
2.In the circuit of Fig .28.50. the ammeter reads 6.0 A and the voltmeter reads 14 V. Find the emf ε and the resistance R.

Fig . 28 . 44 . and Fig .28.50.

http://www.wretch.cc/blog/MAONI2000&article_id=17082282
更新1:

Fig .28.50. → http://www.wretch.cc/album/show.php?i=MAONI2000&b=8&f=1685713071&p=32 Fig . 28 . 44 → http://www.wretch.cc/album/show.php?i=MAONI2000&b=8&f=1685713070&p=31

回答 (2)

2007-06-12 9:46 am
✔ 最佳答案
(1) In accordance to the figure, both terminals of the 7-Ω resistor are connected to the positive terminals of the battery and hence the p.d. across it is zero.
Therefore the current through it is zero.
Then, for the remaining 3-Ω and 4-Ω resistors, they are connected in parallel to the cell and hence both p.d. across them are 10V.
So the current through the 3-Ω resistor = 10/3 A
Current through the 4-Ω resustor = 10/4 = 2.5 A
(2) As follows:

圖片參考:http://i117.photobucket.com/albums/o61/billy_hywung/Jun07/Crazyelectric8.jpg


圖片參考:http://i117.photobucket.com/albums/o61/billy_hywung/Jun07/Crazyelectric9.jpg
參考: My physics knowledge
2007-06-10 6:25 pm
1.resolve the circuit you will get this configuration
As the 7ohm resistor is in short-circuit, current through it = 0 A

─10 V ─
│ │
─3ohm ─
│ │
─4ohm ─

Kirchhoff rule states that I out = I in,
in the setup,
method 1,
equvalent resistance = 12/7
so I out = 10/(12/7) = 5.833
I in 3 ohm : 5.833 x 4/7 = 3.333
I in 4 ohm : 5.833 - 3.333 = 2.500

method 2,
both 3 ohm and 4 ohm resistors have 10 V pd,
by V= IR,
I in 3 ohm = 10/3 = 3.333
I in 4 ohm = 10/4 = 2.5

for the second question, the link of image is not availabe.
參考: me


收錄日期: 2021-04-26 16:20:27
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070610000051KK00990

檢視 Wayback Machine 備份