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Not sure what the initial temperature is

  • Thread starter Gemy4
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  • #1
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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 celcius)
R0=1.59 x 10^-8 ohm*m (The resistivity coefficient of silver at 20 degrees celcius)
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 celcius.

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:

Answers and Replies

  • #2
berkeman
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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
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?
 
  • #3
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Sorry edited
 
  • #4
berkeman
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56,654
6,558


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...
 
  • #5
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Ok Thank you.
 

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