Potential difference between points d and c in circuit

  • Thread starter Omar FTM
  • Start date
  • #1
12
0

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
 

Answers and Replies

  • #2
gneill
Mentor
20,805
2,785
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?
 
  • #3
19
2
There's 3 circuits...
 
  • #4
12
0
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.

There's 3 circuits...
There are only two batteries and 3 resistors.
 
  • #5
gneill
Mentor
20,805
2,785
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.
 
  • #6
12
0
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.
 
  • #7
gneill
Mentor
20,805
2,785
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.
 
  • #8
19
2
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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