How Does Resistivity Affect Copper Wire Resistance and Current Flow?

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SUMMARY

The discussion centers on calculating the resistance of 12-gauge copper wire, specifically 11.5 meters in length, at 20°C using the resistivity of copper, which is 1.7E-8 ohm meters. The resistance was calculated using the formula R=ρ(L/A), where the area A was determined to be 3.33E-6 m². The final resistance calculated was 0.0587 ohms. The error in the initial calculation was identified as a misunderstanding related to significant figures.

PREREQUISITES
  • Understanding of electrical resistance and Ohm's Law
  • Familiarity with the formula R=ρ(L/A)
  • Knowledge of significant figures in scientific calculations
  • Basic geometry for calculating the area of a circle
NEXT STEPS
  • Review the principles of Ohm's Law and its applications
  • Study the significance of significant figures in engineering calculations
  • Learn about the properties of materials, focusing on resistivity
  • Explore advanced calculations involving series and parallel resistances
USEFUL FOR

Electrical engineers, physics students, and anyone involved in circuit design or analysis will benefit from this discussion, particularly those working with copper wiring and resistance calculations.

Snape1830
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12-gauge copper wire has a radius of 1.03×10−3 m. (a) What is the resistance of 11.5 m of this wire at 20°C. (b) How much current will pass through the wire if a potential difference of 9.00 V is applied across it?
The resistivity for copper is 1.7E-8 ohm meters
For part a:
The equation is R=ρ(L/A) and A=∏r2.
I solved for Area and got 3.33E-6 m2.
Then I did R=1.7E-8(11.5/3.33E-6)
R=.0587 ohms.

However, when I plug this into the system it says it's wrong. What did I do incorrectly? I double-checked my multiplication and everything.
 
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Never mind, it was sig figs
 

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