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Resistance Formula:
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Electrical resistance is a measure of the opposition to the flow of electric current through a conductor. It depends on the material's resistivity, the conductor's length, and its cross-sectional area.
The calculator uses the fundamental resistance formula:
Where:
Explanation: Resistance increases with length and decreases with cross-sectional area, while resistivity is an intrinsic property of the material.
Details: Accurate resistance calculation is crucial for designing electrical circuits, selecting appropriate wire sizes, preventing voltage drops, and ensuring electrical safety in various applications.
Tips: Enter resistivity in Ω·m, length in meters, and cross-sectional area in square meters. All values must be positive numbers greater than zero.
Q1: What is resistivity and how is it different from resistance?
A: Resistivity is an intrinsic property of a material that quantifies how strongly it opposes electric current, while resistance depends on both the material and the conductor's dimensions.
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, Iron: 1.0×10⁻⁷ Ω·m.
Q3: Why does resistance increase with length?
A: Longer conductors provide more obstacles for electrons to overcome, increasing the overall opposition to current flow.
Q4: Why does resistance decrease with larger cross-sectional area?
A: Larger cross-sectional areas provide more pathways for electrons to flow, reducing the overall resistance.
Q5: Does temperature affect resistance?
A: Yes, for most conductors, resistance increases with temperature due to increased atomic vibrations that impede electron flow.