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Calculate the resistance of iron if

  • Thread starter looi76
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  • #1
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Homework Statement


A rectangle bar of iron is [tex]2cm[/tex] by [tex]2cm[/tex] in cross section. Calculate its resistance if the resistivity of iron is [tex]11 \times 10^{-8}\Omega{m}[/tex].

Homework Equations



[tex]R = \frac{Pl}{A}[/tex]

The Attempt at a Solution



[tex]R = \frac{Pl}{A}[/tex]

[tex]A = 2 \times 2 \times 10^-4 = 4 \times 10^{-4}m[/tex]
[tex]P = 11 \times 10^{-8}\Omega{m}[/tex]

How is it possible to find the resistance If I don't have the length?
 

Answers and Replies

  • #2
G01
Homework Helper
Gold Member
2,665
16

How is it possible to find the resistance If I don't have the length?
It isn't.

Maybe they are looking for the resistance per unit length:

[tex]\frac{R}{\ell}=\frac{\rho}{A}[/tex]
 

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