Not sure what the initial temperature is

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Homework Help Overview

The discussion revolves around determining the temperature at which aluminum's resistivity is three times that of tungsten's resistivity at room temperature. The problem involves resistivity coefficients and temperature coefficients of resistivity for aluminum and tungsten.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants attempt to use the resistivity equation to find the temperature, questioning the initial temperature assumption of 20 degrees Celsius. There are requests for clarification on terms and units used in the calculations.

Discussion Status

The discussion is ongoing, with participants providing feedback on definitions and units. Some confusion exists regarding the definition of "room temperature" and the consistency of terms used in the problem statement.

Contextual Notes

There is uncertainty about the initial temperature assumption and the definition of "room temperature," which may affect the calculations. Participants are encouraged to clarify terms and ensure consistent units are used.

Gemy4
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Homework Statement



At what temperature will aluminum have a resistivity that is three times the resistivity of tungsten at room temperature?

Rt=5.6 X 10^-8 ohm*m (The resistivity coefficient of tungsten at 20 degrees celsius)
R0=1.59 x 10^-8 ohm*m (The resistivity coefficient of silver at 20 degrees celsius)
α =3.9 X 10^-3 degrees celsius ^- 1 (Temperature coefficient of resistivity for aluminum)

ΔT= Tf-Ti

I am not sure what the initial temperature is, I assume its 20 degrees celsius.

Homework Equations


Rt = R0 * ( 1 + α * ΔT)

The Attempt at a Solution



3Rt = R0 * ( 1 + α * ΔT)I get 11.42 degrees celsius which is wrong?
 
Last edited:
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Gemy4 said:

Homework Statement



At what temperature will aluminum have a resistivity that is three times the resistivity of tungsten at room temperature?

Rt=5.6 X 10^-8
R0=1.59 x 10^-8
α =3.9 X 10^-3
Room temperature = 20 C*

Homework Equations


Rt = R0 * ( 1 + α * ΔT)


The Attempt at a Solution



(3)Rt = R0 * ( 1 + α * ΔT)


I get 11.42 degrees celsius which is wrong?

Could you please define each of the terms that you're using, and include units on everything?
 


Sorry edited
 


Gemy4 said:
Sorry edited

That helps, but you define Rt as two different things (a bit confusing), and the units of resistivity are not Ohm/m.

Does the problem define "room temperature"? 20C is a little low for the room temperature number that I usually use...
 


Ok Thank you.
 

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