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Resistivity Formula:
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Resistivity (ρ) is a fundamental property of materials that quantifies how strongly they oppose electric current. It's an intrinsic property that depends on the material's composition and temperature, independent of its shape or size.
The calculator uses the resistivity formula:
Where:
Explanation: This formula relates the resistance of a uniform material to its physical dimensions and intrinsic resistivity property.
Details: Resistivity calculation is crucial for material selection in electrical engineering, designing conductors and insulators, quality control in manufacturing, and understanding material properties for various applications.
Tips: Enter resistance in ohms (Ω), cross-sectional area in square meters (m²), and length in meters (m). All values must be positive numbers greater than zero.
Q1: What is the difference between resistance and resistivity?
A: Resistance depends on both the material and its dimensions, while resistivity is an intrinsic property of the material itself, independent of size or shape.
Q2: What are typical resistivity values for common materials?
A: Copper: ~1.68×10⁻⁸ Ω·m, Aluminum: ~2.82×10⁻⁸ Ω·m, Glass: ~10¹⁰-10¹⁴ Ω·m, Rubber: ~10¹³-10¹⁶ Ω·m.
Q3: How does temperature affect resistivity?
A: For most metals, resistivity increases with temperature. For semiconductors, resistivity decreases with temperature. Some materials like constantan show minimal change.
Q4: What units are used for resistivity?
A: The SI unit is ohm-meter (Ω·m), but ohm-centimeter (Ω·cm) is also commonly used (1 Ω·m = 100 Ω·cm).
Q5: Why is resistivity important in material science?
A: Resistivity helps classify materials as conductors, semiconductors, or insulators, and is critical for designing electronic components, power transmission systems, and electrical insulation.