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Homework Help: Calculating Voltage Drop

  1. Jul 6, 2008 #1
    Im going to college first year in sept for Mechtronics and im reading in advance for electricity which i know is guna give me problems.

    Right now im stuck on this question. Dont tell me the answer but rather how if find it.

    27) A 6V source is connected to a 100 ohm resistor by two 12 ft lengths of 18 guage copper wire. The total resistance is the resistance of both wires added to the 100 ohm resistor. Determine the following:

    a) Current
    b) Resistor Voltage Drop
    c) Voltage drop across each length of wire

    For reference, resistance (ohm/1000ft at 20 degrees) for 18 AWG copper wire is 6.385 and area is 1624.3cm

    I figured out a. by dividing Voltage (6v) by Total resistance including the wires (100.094 ohms) and got the answer 60 mA.

    Any help with b and c is appreciated
  2. jcsd
  3. Jul 6, 2008 #2


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    Science Advisor
    Gold Member

    For b and c you need to look into voltage dividers. What you have is three resistors in series. The voltage drop across all of them is 6V. Now you need to find the drops across each. Your total should be 6V. Here's a good reference: http://en.wikipedia.org/wiki/Voltage_divider" [Broken]
    Last edited by a moderator: May 3, 2017
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