Home
Back
Resistivity Formula:
| From: | To: |
Electrical resistivity 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, independent of its shape or size.
The calculator uses the resistivity formula:
Where:
Explanation: The formula shows that resistivity is directly proportional to resistance and cross-sectional area, and inversely proportional to length. This relationship allows us to calculate the intrinsic property of a material regardless of its dimensions.
Details: Resistivity calculations are crucial for material selection in electrical engineering, designing conductors and insulators, quality control in manufacturing, and understanding material properties for various applications including electronics, power transmission, and semiconductor devices.
Tips: Enter resistance in ohms, cross-sectional area in square meters, and length in meters. All values must be positive numbers greater than zero. Ensure consistent units for accurate results.
Q1: What's 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, Glass: ~10¹² Ω·m, Silicon: ~2.3×10³ Ω·m (varies with doping).
Q3: How does temperature affect resistivity?
A: For most metals, resistivity increases with temperature. For semiconductors, resistivity decreases with temperature. Some materials like nichrome have relatively constant resistivity over temperature ranges.
Q4: What are the SI units for resistivity?
A: The SI unit is ohm-meter (Ω·m), though ohm-centimeter (Ω·cm) is also commonly used in some applications (1 Ω·m = 100 Ω·cm).
Q5: When is this formula most accurate?
A: The formula is most accurate for uniform, homogeneous materials with constant cross-section and at constant temperature. It assumes uniform current distribution.