How do you find the diameter of a wire

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SUMMARY

The discussion focuses on calculating the diameter of a copper wire given its resistance, mass, resistivity, and density. The relevant equations include Ohm's Law (V=IR) and the resistance formula R=ρL/A, where ρ is resistivity, L is length, and A is cross-sectional area. To find the diameter, one must first derive the length from the mass and density, then use the area formula A=4πr² to solve for the radius, which is subsequently doubled to obtain the diameter. The specific values provided include a resistance of 17.00 Ω, a mass of 37.0 g, a resistivity of 1.68×10-8 Ω·m, and a density of 8.90×103 kg/m³.

PREREQUISITES
  • Understanding of Ohm's Law (V=IR)
  • Familiarity with the resistance formula R=ρL/A
  • Knowledge of mass density and its application in calculations
  • Basic geometry for calculating the area of a circle (A=πr²)
NEXT STEPS
  • Learn how to derive length from mass and density using the formula L = mass/density
  • Study the relationship between resistance, resistivity, and dimensions of conductors
  • Explore the implications of resistivity in different materials, particularly copper
  • Practice solving similar problems involving electrical resistance and wire dimensions
USEFUL FOR

Students in physics or electrical engineering, educators teaching circuit theory, and anyone involved in materials science or electrical design who needs to calculate wire dimensions based on electrical properties.

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Homework Statement


I have a question where I'm given the voltage, mass, resistivity, and density of a wire and I need to find the diameter and the length. Can someone show me how to do both of these?


Homework Equations



I have no idea what equation would relate voltage, mass, resistivity, and density to the diameter and length.
 
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Heres a hint. R=pL/A (p is rho). Find another equation to this and solve for the radius in A and times that by 2 which will give you your diameter
 
The actual question is:
A 17.00 Ω resistor is made from a coil of copper wire whose total mass is 37.0 g. The resistivity of Cu is 1.68×10-8 Ω · m and its mass density is 8.90×103 kg/m3. What is the diameter of the wire?

So would I use Ohm's law V=IR to find I?
 
Im not totally sure but, you are given the mass density (kg/m^3). If you can find a way to get a length out of that (meters), you can use the formula I gave you and solve for A.
A=4∏r^2, then solve for r and times that by 2
 
How should I get a length out of the density?
 
Try 1 m^4/ mass (kg) units will cancel out leaving you with m
 

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