Simple Error Could use some help

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Discussion Overview

The discussion revolves around a calculation error in an electrical circuit problem involving resistances R1 and R2. Participants are examining the implications of their calculations and the relevance of R2 in determining the current.

Discussion Character

  • Homework-related
  • Debate/contested

Main Points Raised

  • One participant calculated the total resistance as 8.571 ohms and derived currents I and I' from this value, leading to a difference of 0.013.
  • Another participant suggests that R2 may be irrelevant to the calculation, questioning the necessity of including it in the problem.
  • A later reply acknowledges the initial belief about R2's relevance but expresses uncertainty about the teacher's intentions in including it.
  • Some participants reflect on the educational value of the problem, suggesting that it teaches an additional concept despite the confusion.

Areas of Agreement / Disagreement

Participants express differing views on the relevance of R2 in the problem, indicating that there is no consensus on its necessity for the calculations.

Contextual Notes

There are unresolved assumptions regarding the role of R2 in the circuit and the calculations leading to the difference in current values. The participants do not clarify the definitions or conditions under which their calculations were made.

xpack
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http://img401.imageshack.us/img401/3074/38927294.png I added r1 and r2 together to produce 8.571 and made
I=10/8.571
and
I'=10/8.671
and subtracted I from I' and got .013
But my teacher marked the answer as .004

How is this?
 
Last edited by a moderator:
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xpack said:
http://img401.imageshack.us/img401/3074/38927294.png


I added r1 and r2 together to produce 8.571 and made
I=10/8.571
and
I'=10/8.671
and subtracted I from I' and got .013
But my teacher marked the answer as .004

How is this?

I believe R2 is irrelevant to this question.

The delta-I comes about because in one case you have 10V across R1, and in the other case, you have 10V across <what?>...
 
Last edited by a moderator:
Oh okay thanks, that's what I thought but I didn't think the teacher would put an r2 if it wasn't relevant guess I was wrong.
 
xpack said:
Oh okay thanks, that's what I thought but I didn't think the teacher would put an r2 if it wasn't relevant guess I was wrong.

Yes, it's a little sneaky, but it helped to teach you something extra on this problem, so it's worthwhile. :smile:
 

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