Home
Back
Resistivity Formula:
| From: | To: |
Resistivity is a fundamental property of materials that quantifies how strongly they oppose electric current. It is an intrinsic property that depends on the material's composition and temperature, independent of 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: 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 for accurate calculation.
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 size or 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, Silver: 1.59×10⁻⁸ Ω·m, Glass: 10¹⁰-10¹⁴ Ω·m, Rubber: 10¹³-10¹⁶ Ω·m.
Q3: How does temperature affect resistivity?
A: For most conductors, resistivity increases with temperature. For semiconductors, resistivity decreases with temperature. The relationship is described by temperature coefficients.
Q4: Why is resistivity important in wire selection?
A: Lower resistivity materials are preferred for conductors to minimize power loss, while higher resistivity materials are used for insulation and heating elements.
Q5: Can resistivity be measured directly?
A: No, resistivity is calculated from measured resistance and dimensional measurements using the formula ρ = RA/L. Specialized equipment like four-point probes are used for accurate measurements.