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Specific Resistance Formula:
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Specific resistance (also known as resistivity) is an intrinsic property of materials that quantifies how strongly they oppose electric current. It is defined as the resistance of a unit cube of the material measured between opposite faces.
The calculator uses the specific resistance formula:
Where:
Explanation: The formula shows that specific resistance depends on the material's inherent properties and is independent of its dimensions, unlike regular resistance which depends on both material and geometry.
Details: Specific resistance is crucial for material selection in electrical engineering, designing conductors and insulators, calculating power losses in transmission lines, 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 specific resistance?
A: Resistance depends on both material and geometry, while specific resistance is an intrinsic property of the material itself, independent of shape and size.
Q2: What are typical specific resistance 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 specific resistance?
A: For most conductors, specific resistance increases with temperature. For semiconductors, it typically decreases with temperature.
Q4: What are the units of specific resistance?
A: The SI unit is ohm-meter (Ω·m), but ohm-centimeter (Ω·cm) is also commonly used in some applications.
Q5: Why is specific resistance important in material science?
A: It helps classify materials as conductors, semiconductors, or insulators, and is essential for designing electronic components and electrical systems.