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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 measured resistance of a uniform material to its intrinsic resistivity, accounting for the material's dimensions.
Details: Resistivity calculations are essential for material science, electrical engineering, and electronics design. They help in selecting appropriate materials for wires, resistors, and other electrical components based on their conductive properties.
Tips: Enter resistance in ohms, cross-sectional area in square meters, and length in meters. All values must be positive numbers greater than zero.
Q1: What's the difference between resistance and resistivity?
A: Resistance depends on both material properties and geometry, while resistivity is an intrinsic property of the material itself, independent of size and 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.
Q4: What units should I use for area and length?
A: Use square meters for area and meters for length to get resistivity in ohm-meters. You can convert from other units as needed.
Q5: Can this formula be used for non-uniform materials?
A: This formula assumes a uniform material with constant cross-section. For non-uniform materials, more complex calculations are required.