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Homework Help: Find change in resistance for mercury-tube breathing monitor

  1. May 2, 2004 #1
    AP Physics Help--Emergency

    My physics teacher sometimes gives out rediculously difficult worksheets. I'm having trouble with one problem in particular:

    A breathing monitor girds a patient with a mercury-filled rubber tube and measures the variation on tube resistance. The tube has an unstretched length of 1.25 m and inside diameter of 2.51 mm. The monitor is connected to a 100-mV power supply, and the total resistance of the circuit is that due to the mercury plus 1.00 Ω (an internal resistance of the power supply). Determine the change of current through the monitor as the patient draws a breath and stretches the hose by 10.0 cm. Take ρ(Hg) = 9.40 x 10^(-7) Ω ◦ m.

    Any help would be greatly appreciated.
  2. jcsd
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