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Resistivity Formula:
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Resistivity (ρ) is an intrinsic property of materials that quantifies how strongly they oppose electric current. For copper, the standard resistivity is approximately 1.68 × 10⁻⁸ Ω·m at 20°C, making it an excellent conductor.
The calculator uses the resistivity formula:
Where:
Explanation: This formula calculates the intrinsic resistivity of a material by measuring the resistance of a wire sample with known dimensions.
Details: Resistivity is crucial for material selection in electrical engineering, determining conductor efficiency, designing electrical systems, and quality control in manufacturing.
Tips: Enter resistance in ohms (Ω), cross-sectional area in square meters (m²), and length in meters (m). All values must be positive and non-zero. For copper wire, the calculated resistivity should be close to 1.68 × 10⁻⁸ Ω·m.
Q1: What is the standard resistivity of copper?
A: Pure copper has a resistivity of approximately 1.68 × 10⁻⁸ Ω·m at 20°C, though this varies slightly with purity and temperature.
Q2: How does temperature affect resistivity?
A: Resistivity increases with temperature for conductors like copper. The temperature coefficient for copper is about 0.00393 per °C.
Q3: What units should I use for cross-sectional area?
A: Use square meters (m²) for consistency with SI units. For wire gauges, convert from mm² to m² by multiplying by 10⁻⁶.
Q4: Why is copper commonly used in electrical wiring?
A: Copper has low resistivity, excellent conductivity, good mechanical properties, and resistance to corrosion, making it ideal for electrical applications.
Q5: How accurate is this calculation for real-world applications?
A: The calculation provides theoretical resistivity. Actual values may vary due to impurities, temperature variations, and manufacturing processes.