DC circuit, find current and potential

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Discussion Overview

The discussion revolves around solving a problem related to a DC circuit, specifically calculating the current through a 5Ω resistor and determining the potential at a specific point labeled 'a'. The scope includes applying Kirchhoff's laws and circuit analysis techniques.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • The original poster requests assistance with calculating the current through a 5Ω resistor and the potential at point 'a', indicating difficulty with applying Kirchhoff's laws.
  • One participant suggests that the original poster must show their attempts at using Kirchhoff's laws, including equations and a diagram, to receive more targeted help.
  • The original poster shares their attempts, outlining four loops and the corresponding equations derived from Kirchhoff's current law, but expresses uncertainty about their progress.
  • Another participant recommends combining the 9Ω and 6Ω resistors to simplify the circuit analysis and suggests using two currents for better clarity in the calculations.

Areas of Agreement / Disagreement

Participants generally agree on the need to apply Kirchhoff's laws for solving the circuit problem, but there is no consensus on the correctness of the original poster's approach or the specific steps to take next.

Contextual Notes

There are limitations in the original poster's equations and the clarity of the circuit diagram, which may affect the analysis. The discussion does not resolve whether the proposed combinations of resistors or the suggested methods are the most effective.

sabak22
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https://www.physicsforums.com/attachments/39765

a) Calculate the current through the 5Ω resistance. Use '+' sign for the current directed from right to left, and '-' sign if the current flows from left to right.

b) The magnitude of the potential at 'a' is?


Please help me with the two questions above. I have tried to used the Kirchoff's law. but it doesn't seem to work for me. Thank you in advance!

(clicK on the picture to view the circuit)
 
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sabak22 said:
https://www.physicsforums.com/attachments/39765

a) Calculate the current through the 5Ω resistance. Use '+' sign for the current directed from right to left, and '-' sign if the current flows from left to right.

b) The magnitude of the potential at 'a' is?


Please help me with the two questions above. I have tried to used the Kirchoff's law. but it doesn't seem to work for me. Thank you in advance!

(clicK on the picture to view the circuit)

You would really have to show your attempt at using Kirchoff's Laws, including the equations and a diagram showing the currents and voltages referred to in the equations.

Without that, we would have to just do the problem for you and that is against the rules here and also wouldn't do you any good.
 
here are my attempts:

First i made 4 different loops. each one of them looking like this by using Kirchoff's current law:

A) 19-9I3-6I4+7-5I1=0
B) 7-5I1-16I2=0
C) 7-5I1+19-9I3-6I4=0
D) 19-9I3-6I4+16I2=0

But now I feel like I am stuck I don't know what to do. I don't even know if I am on the right track or not. I need help
 
You can combine the 9 ohm and 6 ohm resistors to get 15 ohms. This will cut down on the typing a bit.

Try using two currents. One going right from point "a" and one going down from point "a". The one through the 7V battery can be derived from these two currents.

Modify the first diagram to show the new currents and the polarities of the voltages across the resistors.
 

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