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Homework Help: Electric Circuit

  1. Jan 8, 2012 #1
    What does the slope of a length vs. resistance graph tell you?

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


    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
  2. jcsd
  3. Jan 8, 2012 #2


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    Firstly how does resistance relate to length? (think of resistivity of a material)

    Secondly what does Ohm's law state?
  4. Jan 8, 2012 #3
    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.
  5. Jan 8, 2012 #4


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    So what formula relates resistance and length?

    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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