Is the Resistance of this Easy Circuit Really Just 10 Ohms?

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Homework Help Overview

The discussion revolves around determining the equivalent resistance of a circuit involving resistors, specifically questioning whether the total resistance is indeed 10 ohms. The original poster expresses confusion regarding the configuration of the resistors and their impact on the circuit's resistance.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to reason through the circuit's behavior by applying Ohm's law and questioning the role of a resistor that appears to have no current flowing through it. Some participants provide insights on the implications of short circuits and equivalent resistance in series and parallel configurations.

Discussion Status

The conversation includes varying interpretations of how current behaves in the presence of a short circuit. While some participants affirm the original poster's reasoning, others suggest reconsidering the flow of current and the analogy of current taking the path of least resistance. There is no explicit consensus, but multiple perspectives are being explored.

Contextual Notes

Participants are navigating the complexities of circuit analysis, particularly in distinguishing between series and parallel configurations, and the implications of short circuits on overall resistance. The original poster's uncertainty about their understanding is evident, and assumptions about current flow are being questioned.

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Is the resistance of this circuit 10 ohms?

http://img75.imageshack.us/img75/9229/littlecircuitro8.jpg

I can't prove anything to myself since the resistors aren't in parallel or series.

I do notice that the potential at the top of the right side resistor is the same as at the bottom... So by Ohm's law the current through it should be zero, and so it's just sitting there not resisting anything. Hence, only the left resistor provides resistance to the circuit and R_total = 10 ohms.

Am I correct? Because this just seems counter intuitive.Thanks!
 
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You are correct. I don´t see why do you say it is counter intuitive.
The equivalent resistance of a resistor in parallel with a short-circuit is a short circuit.
The equivalent resistance of a resistor in series with a short-circuit is the resistance of the resistor.
 
I dunno... It just seems to me like perhaps a little bit of the current would get through. :smile:

I guess if I looked at it as the current taking the path of least resistance, then yeah, I guess it's pretty intuitive. (Although, obviously, such an analogy couldn't extend to resistors in parallel)

Anyways... Thanks!
 
jmcgraw said:
I dunno... It just seems to me like perhaps a little bit of the current would get through. :smile:

I guess if I looked at it as the current taking the path of least resistance, then yeah, I guess it's pretty intuitive. (Although, obviously, such an analogy couldn't extend to resistors in parallel)

Anyways... Thanks!
Such analogy extends to resistors in parallel. The short-circuit has zero resistance, so all the current passes through it.
 

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