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Conductivity and Resistivity Formula:
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The conductivity and resistivity formula describes the inverse relationship between electrical conductivity (σ) and electrical resistivity (ρ). Conductivity measures how well a material conducts electric current, while resistivity measures how strongly a material opposes electric current flow.
The calculator uses the fundamental formula:
Where:
Explanation: This formula shows that materials with high resistivity have low conductivity, and vice versa. Good conductors like copper have high conductivity and low resistivity, while insulators have low conductivity and high resistivity.
Details: Understanding the relationship between conductivity and resistivity is crucial for material selection in electrical engineering, electronics design, and understanding material properties for various applications including wiring, semiconductors, and insulation materials.
Tips: Enter the resistivity value in Ohm-meters (Ω·m). The value must be greater than zero. The calculator will automatically compute the corresponding conductivity in Siemens per meter (S/m).
Q1: What are typical resistivity 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.
Q2: How does temperature affect conductivity and resistivity?
A: For most metals, resistivity increases with temperature, causing conductivity to decrease. For semiconductors, the relationship is more complex.
Q3: What is the difference between conductivity and conductance?
A: Conductivity is an intrinsic property of the material, while conductance depends on the material's dimensions (length and cross-sectional area).
Q4: Why are some units in S/m and others in Ω·m?
A: Siemens (S) is the SI unit of electrical conductance, and Ohm (Ω) is the SI unit of electrical resistance. S/m and Ω·m are the respective derived units for conductivity and resistivity.
Q5: Can this formula be used for all materials?
A: This basic formula applies to homogeneous, isotropic materials. For anisotropic materials or at very high frequencies, more complex models may be needed.