Home
Back
Formula Used:
| From: | To: |
The resistance formula R = ρ * (l/A) calculates the electrical resistance of a material based on its resistivity (ρ), the distance between electrodes (l), and the cross-sectional area of the electrode (A). This fundamental equation in electrical engineering helps determine how much a material opposes the flow of electric current.
The calculator uses the resistance formula:
Where:
Explanation: The formula shows that resistance is directly proportional to both the material's resistivity and the distance between electrodes, and inversely proportional to the cross-sectional area of the electrode.
Details: Accurate resistance calculation is crucial for designing electrical circuits, selecting appropriate materials for conductors, determining power loss in transmission lines, and ensuring proper functioning of electronic devices.
Tips: Enter resistivity in Ω·m, distance between electrodes in meters, and cross-sectional area in m². All values must be positive numbers greater than zero.
Q1: What is resistivity and how does it affect resistance?
A: Resistivity is an intrinsic property of materials that measures how strongly they oppose electric current. Higher resistivity means higher resistance for the same dimensions.
Q2: Why does cross-sectional area affect resistance?
A: Larger cross-sectional area provides more pathways for electrons to flow, reducing the resistance to current flow.
Q3: 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.
Q4: How does temperature affect resistance?
A: For most conductors, resistance increases with temperature due to increased atomic vibrations that impede electron flow.
Q5: What are the practical applications of this formula?
A: This formula is used in designing electrical wiring, calculating power transmission losses, designing resistors, and analyzing material properties for electrical applications.