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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 flow. It's measured in ohm-meters (Ω·m) and depends on the material's composition and temperature, but not on its dimensions.
The calculator uses the resistivity formula:
Where:
Explanation: This formula relates the material's intrinsic resistivity to its measured resistance and physical 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's 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: Conductors like copper have low resistivity (~1.68×10⁻⁸ Ω·m), semiconductors like silicon have moderate values, and insulators like glass have very high resistivity (>10¹⁰ Ω·m).
Q3: How does temperature affect resistivity?
A: For most metals, resistivity increases with temperature. For semiconductors, resistivity typically decreases with temperature.
Q4: What units should I use for cross-sectional area?
A: Use square meters (m²) for consistency with SI units. You can convert from mm² by dividing by 1,000,000.
Q5: Can this formula be used for any material shape?
A: This formula applies specifically to uniform materials with constant cross-sectional area along their length, such as wires or rods.