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Electrical Resistivity Formula:
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Electrical resistivity (ρ) is a fundamental property that quantifies how strongly a material opposes the flow of electric current. It's an intrinsic property that depends on the material's composition and temperature, not its shape or size.
The calculator uses the resistivity formula:
Where:
Explanation: This formula relates the resistance of a material to its physical dimensions and intrinsic resistivity property. The resistivity remains constant for a given material at a specific temperature.
Details: Calculating resistivity 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 shape or size.
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 resistivity, and insulators like glass have very high resistivity (>10¹² Ω·m).
Q3: How does temperature affect resistivity?
A: For most metals, resistivity increases with temperature. For semiconductors, resistivity typically decreases with temperature. The relationship is described by temperature coefficients.
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, where 1 Ω·m = 100 Ω·cm.
Q5: Why is resistivity important in practical applications?
A: Resistivity determines material suitability for electrical wiring (low resistivity), insulation (high resistivity), heating elements, and electronic components.