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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, but not on its shape or size.
The calculator uses the resistivity formula:
Where:
Explanation: This formula calculates the material's inherent resistivity by relating the measured resistance to the wire's physical dimensions.
Details: Resistivity is crucial for material selection in electrical applications, quality control in manufacturing, and understanding material properties in research and development.
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 material and geometry, 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: Copper: ~1.68×10⁻⁸ Ω·m, Aluminum: ~2.82×10⁻⁸ Ω·m, Silver: ~1.59×10⁻⁸ Ω·m, Glass: ~10¹⁰-10¹⁴ Ω·m.
Q3: How does temperature affect resistivity?
A: For most metals, resistivity increases with temperature. For semiconductors, resistivity typically decreases with temperature.
Q4: How do I measure cross-sectional area for non-circular wires?
A: For rectangular wires, multiply width by height. For irregular shapes, use geometric formulas or direct measurement techniques.
Q5: Why is resistivity important in electrical engineering?
A: It helps select appropriate materials for specific applications, design efficient circuits, and predict electrical performance in various conditions.