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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. It's measured in ohm-meters (Ω·m) and depends on the material's composition and temperature.
The calculator uses the resistivity formula:
Where:
Explanation: This formula relates the material's intrinsic resistivity to its measured resistance and geometric dimensions. The resistance increases with length and decreases with cross-sectional area.
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 is a property of a specific object, while resistivity is an intrinsic property of the material itself, independent of the object's 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, Silicon: ~6.4×10² Ω·m, Glass: ~10¹⁰-10¹⁴ 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 have nearly constant resistivity.
Q4: What are the units 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 essential for designing electrical components, wiring systems, and electronic devices.