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Another thermodynamics

  • Thread starter ice87
  • Start date
25
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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:

Answers and Replies

lightgrav
Homework Helper
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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?
 
Andrew Mason
Science Advisor
Homework Helper
7,549
318
ice87 said:
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:
I think you need more information in order to answer b).

AM
 
25
0
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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