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Equivalent resistance

  • Thread starter jackxxny
  • Start date
  • #1
39
0

Homework Statement



I need to find the equivalent resistance of the network outside the battery, and the current in resistor R2. the picture of my circuit is attached.

R1= 10 ohms
R2 = 6 ohms
R3 = 5 ohms
R4 = 30 ohms

Homework Equations



series Req= R1+R2...
parallel 1/Req= 1/R1+1/R2....

The Attempt at a Solution




I have a lot of trouble sseing this picture. i think is this:


R2-4 = 36 ohms
R1-3 = 1/(.3)= 3.333 ohms
Req= 36 + 3.33 = 39.333 ohms

is it right how i split them?

and would it the current trough resistor 2 just be:

V=IR 30/6 = 5 Ampere

????
 

Attachments

Answers and Replies

  • #2
LowlyPion
Homework Helper
3,090
4
So you have R2 + R4 + (R1 || R3) = 39.333 ?
(I can't see your picture as yet.)

What is the voltage across the whole thing?
 
  • #3
39
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when i broke it down in parallel and series, i'm not quite sure if i can assume that R1 and R3 are in parallel. Then i put togheter R4 and R2 as in series and plus R13 in series too..
but i don't know if i can do that.
 
  • #4
LowlyPion
Homework Helper
3,090
4
when i broke it down in parallel and series, i'm not quite sure if i can assume that R1 and R3 are in parallel. Then i put togheter R4 and R2 as in series and plus R13 in series too..
but i don't know if i can do that.
Well, since I can't see the picture I'll have to wait. If you don't know whether you can, that is if it is not obviously that way, then ... we'll wait.
 
  • #5
39
0
What's worng with the picture?
 

Attachments

  • #6
LowlyPion
Homework Helper
3,090
4
What's worng with the picture?
It's the part that says:
Attachments Pending Approval
 
  • #7
39
0
so does that mean that my picture is getting approve from someone??
how long does it take?
 
  • #8
LowlyPion
Homework Helper
3,090
4
so does that mean that my picture is getting approve from someone??
how long does it take?
The picture is viewable now. Just depends on when someone gets around to approving it. Imageshack is an alternative way to get a jpg up a little faster.

Looking at your topography, consider redrawing and seeing if you don't find that you have :

((R2 || R4) + R3) || R1
 
  • #9
ideasrule
Homework Helper
2,266
0
Well, it's approved now.
Imagine an electron travelling from the right side of the battery to the left side. At first, it can either go through R1 or the branch containing R3 (not R3 itself), so R1 is in parallel with the branch containing R3.

What's the resistance of the branch containing R3? Remember that if the electron passes through this branch, it must pass R3, but after that, it has a choice between R2 and R4. In other words, R2 and R4 are in parallel; R3 is in series.
 

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