Potential difference between points d and c in circuit

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Homework Help Overview

The discussion revolves around calculating the potential difference between two points in a circuit involving two batteries and three resistors. The original poster attempts to apply superposition to find the current through one of the resistors but expresses uncertainty about their final answer.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the direction of current flow and its effect on potential difference. There is mention of separating the circuit into two parts for calculations and concerns about the accuracy of intermediate rounding in calculations.

Discussion Status

Participants are actively engaging with the problem, questioning the assumptions about current flow and potential differences. Some guidance has been offered regarding the need for precision in calculations, and there is a recognition of the circuit's configuration with batteries and resistors.

Contextual Notes

There is some confusion regarding the number of circuits and components involved, with participants noting the presence of two batteries and three resistors while discussing the overall circuit setup.

Omar FTM
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Homework Statement


In the figure below, what is the potential difference Vd - Vc between points d and c if E1(of 1st battery) = 4.7 V, E2((of 2nd battery) = 1.4 V, R1 = R2 = 11 Ω, and R3 = 6.7 Ω, and the batteries are ideal?
http://farm6.static.flickr.com/5053/5469093809_53c7fe57f4.jpg

Homework Equations


V= IR

The Attempt at a Solution


I used superposition in order to find the current at R2 which leads to V2 = I2R2.
I separated the circuit into two circuits , each with one battery and its own calculations then I added them together , but the final answer seems wrong for an unknown reason...
https://scontent-sin6-1.xx.fbcdn.net/v/t35.0-12/15302523_1489883864359796_661161770_o.jpg?oh=7c4c036aa34ea2f78ce415299ea1557d&oe=58425946
 
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What is the direction of flow of the final current? Will it cause a potential drop or a potential rise between node d and node c?
 
There's 3 circuits...
 
gneill said:
What is the direction of flow of the final current? Will it cause a potential drop or a potential rise between node d and node c?
The current flow as mentioned is upward on R2.
I tried puting -0.3 v and 0.3v , both were wrong.

SSWheels said:
There's 3 circuits...
There are only two batteries and 3 resistors.
 
Omar FTM said:
The current flow as mentioned is upward on R2.
I tried puting -0.3 v and 0.3v , both were wrong.
Yeah, you'll probably want to conserve more digits through your intermediate calculations.
 
gneill said:
Yeah, you'll probably want to conserve more digits through your intermediate calculations.
But my steps are right , are not they ? I will do it using less rounding this time.
 
Omar FTM said:
But my steps are right , are not they ? I will do it using less rounding this time.
Your steps looked fine when I scanned through your work.
 
Omar FTM said:
The current flow as mentioned is upward on R2.
I tried puting -0.3 v and 0.3v , both were wrong.There are only two batteries and 3 resistors.
Yes, but the two batteries are in series with each other, forming a circuit with R1 & R2
 

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