Math Problem Statement

What is the resistance of a 150 m aluminum wire of radius 1.5 mm ?

Solution

To find the resistance RR of the aluminum wire, we can use the formula:

R=ρLAR = \frac{\rho L}{A}

Where:

  • RR is the resistance.
  • ρ\rho is the resistivity of aluminum (approximately 2.82×108Ωm2.82 \times 10^{-8} \, \Omega \cdot \text{m}).
  • LL is the length of the wire (150 meters).
  • AA is the cross-sectional area of the wire (since the wire is cylindrical, the cross-sectional area is A=πr2A = \pi r^2).

Given:

  • r=1.5mm=0.0015mr = 1.5 \, \text{mm} = 0.0015 \, \text{m},
  • L=150mL = 150 \, \text{m}.

Step 1: Calculate the cross-sectional area AA

A=πr2=π(0.0015)2m2=π×2.25×106m2A = \pi r^2 = \pi (0.0015)^2 \, \text{m}^2 = \pi \times 2.25 \times 10^{-6} \, \text{m}^2

Step 2: Calculate the resistance RR

Now plug the values into the formula:

R=2.82×108×150π×2.25×106R = \frac{2.82 \times 10^{-8} \times 150}{\pi \times 2.25 \times 10^{-6}}

Let me compute that for you.The resistance of the 150-meter aluminum wire with a radius of 1.5 mm is approximately 0.598Ω0.598 \, \Omega.

Would you like more details or have any questions?

Here are 5 related questions:

  1. How does the length of the wire affect its resistance?
  2. What would the resistance be if the wire were made of copper instead of aluminum?
  3. How does temperature affect the resistance of a metal wire?
  4. How would the resistance change if the radius of the wire were doubled?
  5. What are some practical applications of knowing a wire's resistance?

Tip: For wires of the same material, resistance is directly proportional to length and inversely proportional to the cross-sectional area.

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Math Problem Analysis

Mathematical Concepts

Electricity
Resistance
Geometry (Cylindrical Shapes)

Formulas

Resistance formula: R = ρL / A
Area of a circle: A = πr^2

Theorems

Ohm's Law

Suitable Grade Level

Grades 10-12