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Homework Help: Another thermodynamics

  1. Sep 10, 2005 #1
    another thermodynamics problem

    For this one its a combination of the wording and the whole resistance that i dont get.

    In the interval between the freezing point of water and 700 degrees C, a platinum resistance thermometer is used for interpolating the temperatures on the international scale the Celsius temperature Tc is given by a formula for resistance R with temperature
    R = R0(1 + ATc +BTc^2) where A and B are constants determined by measurements at the ice point, the steam point of water, and the melting point of zinc (419.414 degrees C). (a) If R equals 10.000 ohms at the ice point, 13.946 ohms at the steam point, and 24.174 at the melting point of zinc, find R0, A, and B; (b) When immersed in a solution the length is 25.4 cm. What is the temperature of the solution.

    now wtf? :yuck:
     
    Last edited: Sep 10, 2005
  2. jcsd
  3. Sep 11, 2005 #2

    lightgrav

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    Resistance is an electrical property of a device.
    For metals, resistance increases (almost linearly)
    Almost proportional to Temperature in Kelvin.
    So expect B to be small.

    What is Tc of the ice point? What, then, is Ro?
    Do you know what temperature the "steam point" is?
     
  4. Sep 11, 2005 #3

    Andrew Mason

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    I think you need more information in order to answer b).

    AM
     
  5. Sep 11, 2005 #4
    You see what I dont get is where all the numbers go, and what all the letters in the equation represent. I'm guessing for part A i need to setup 3 equations with 3 variables and R equalling 10.000, 13.946, and 24.174 ohms? and maybe with Tc equalling 0, 100, and 419.414 degrees C respectively?
     
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