Not sure what the initial temperature is

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SUMMARY

The discussion focuses on calculating the temperature at which aluminum's resistivity is three times that of tungsten's resistivity at room temperature. The resistivity of tungsten at 20 degrees Celsius is 5.6 x 10^-8 ohm*m, while aluminum has a temperature coefficient of resistivity (α) of 3.9 x 10^-3 degrees Celsius^-1. The equation used is Rt = R0 * (1 + α * ΔT), leading to confusion regarding the initial temperature assumption of 20 degrees Celsius. The incorrect result of 11.42 degrees Celsius indicates a need for clarification on the definitions and units used in the calculations.

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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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