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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 measurable resistance of a material sample to its intrinsic resistivity, taking into account the sample's geometry.
Details: Resistivity calculations are 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's 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 show superconductivity at very low temperatures.
Q4: What units are used for resistivity?
A: The SI unit is ohm-meter (Ω·m). Sometimes ohm-centimeter (Ω·cm) is used, where 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 crucial for selecting appropriate materials for specific electrical applications.