Current flowing from point A in a circuit to point B

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Homework Help Overview

The discussion revolves around a circuit problem involving current flow, resistors, and batteries. The original poster seeks to determine the potential difference between points A and B in a circuit with specified components and values.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the application of voltage drops across resistors and the effects of battery polarity on potential differences. There are questions about the correctness of the original poster's calculations and the need for clarity on the definition of point B.

Discussion Status

Some participants have provided guidance on analyzing the circuit, suggesting that drawing it out may help clarify the voltage changes. There is an ongoing exploration of the assumptions regarding the current flow and the potential at point B.

Contextual Notes

There is some ambiguity regarding the definition of point B, with participants suggesting it may refer to the negative terminal of one of the batteries. The original poster has expressed uncertainty about their calculations and the correctness of their approach.

FADFAD1

Homework Statement


A current at point A of 2A flows through a resistor (3 ohms), a battery of 20V (negative terminal first), another resistor (1 ohm) and a battery of 6V (positive terminal first). What is the potential difference between A and B

Homework Equations

The Attempt at a Solution


I used a negative voltage for when it passes through the first resistor then added 20V through the battery but it doesn't seem right
 
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I think you are correst.
I would say that a current of 2A flows from the rest of the circuit through point A into the 3Ω resistor. Point A has to be more positive than the other side of this resistor to make such a current flow.
 
FADFAD1 said:
I used a negative voltage for when it passes through the first resistor then added 20V through the battery but it doesn't seem right

That is 100% correct. Just keep going. So far you have..

-(2*3) + 20 ...
 
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It might help if you draw the circuit, labeling the voltage drops (or rises) for each device.
You said you did not get the correct answer. (actually you said it doesn't seem right, sorry).
What answer did you get? How did you arrive at that answer? If we can see that, then we can better guide you to where the mistake is.

If current flows through a resistor from left to right, then the left side will be at higher (more positive) potential than the right. Flow through a battery depends on the polarity of the battery. If it goes from negative terminal (through the battery) to positive, then it is a voltage rise.
 
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What is point B?
 
Asymptotic said:
What is point B?
It sounds like B is the negative terminal of the 6 volt battery.
 

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