Electric Circuit: What Slope Tells You

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Homework Help Overview

The discussion revolves around understanding the relationship between resistance and length in electric circuits, specifically through the analysis of graphs depicting length versus resistance and inverse resistance versus current. Participants are exploring the implications of slope in these graphs as part of a lab experiment involving circuit construction and measurements.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants inquire about the relationship between resistance and length, referencing the concept of resistivity. They also discuss Ohm's law and its implications for current and resistance. Questions arise regarding the formulas that relate resistance to length and how to rearrange equations for graphing purposes.

Discussion Status

The discussion is active, with participants sharing insights about the relationship between resistance and length, as well as the principles of Ohm's law. Some participants are seeking clarification on how to express these relationships mathematically for graphing, indicating a productive exploration of the topic.

Contextual Notes

Participants are working within the constraints of a lab assignment, which includes specific measurements and graphing tasks. There is mention of uncertainty regarding the accuracy of voltage measurements and requests for recommendations on graphing tools.

AddversitY
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What does the slope of a length vs. resistance graph tell you?
Slope=?

What does the slope of an inverse resistance vs. current graph tell you?
Slope=?

__________________________________________________________________

Here's what I had to do for my lab:

1: Construct a circuit where I connect a clip onto a wire that allows electricity to flow. Move the clip down the meter stick until you reach 100cm. Result: The farther I moved the clip down the wire the dimmer my light bulb got. The power source was a battery.

2: Measure and record the voltage of the circuit across the battery - this needs to only to be done once. Result: The voltage stayed the same (I do not know if that is correct).

3: Instert an ammeter and measure and record in a table the corresponding current (I) at each position (l).

4: Predict the Resistance (R) at each position.

5: Construct the following:
A) Length (l) vs Resistance (R)
B) Inverse Resistance (1/R) vs Current (I)

My graphs looked like the following: (If anybody has any recommendations on where to create graphs PLEASE tell me, this site isn't too great.)
A = http://www.chartgo.com/share.do?id=d886b9a8aa
B = http://www.chartgo.com/share.do?id=94f8b0fdaa
 
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Firstly how does resistance relate to length? (think of resistivity of a material)

Secondly what does Ohm's law state?
 
rock.freak667 said:
Firstly how does resistance relate to length? (think of resistivity of a material)

Secondly what does Ohm's law state?

1: The greater the length results in more resistance.

2: Ohm's law: The current passing through a conductor between two points is directly proportional to the potential difference (i.e. voltage drop or voltage) across the two points, and inversely proportional to the resistance between them.
 
AddversitY said:
1: The greater the length results in more resistance.

So what formula relates resistance and length?

AddversitY said:
2: Ohm's law: The current passing through a conductor between two points is directly proportional to the potential difference (i.e. voltage drop or voltage) across the two points, and inversely proportional to the resistance between them.

So then you have V = IR, how would you rearrange the formula to get in the form Y=MX where you plotted Y against X?
 

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