1. What is Electrical Resistance?

Electrical resistance is a measure of the opposition to current flow in an electrical circuit. It is measured in ohms (Ω) and depends on the material's resistivity, length, and cross-sectional area of the conductor.

2. How Does the Calculator Work?

The calculator uses the resistance formula:

Where:

• \( R \) — Electrical resistance (Ω)
• \( \rho \) — Resistivity of the material (Ω·m)
• \( L \) — Length of the wire (m)
• \( A \) — Cross-sectional area of the wire (m²)

Explanation: The resistance increases with longer wire length and higher resistivity, but decreases with larger cross-sectional area.

3. Importance of Resistance Calculation

Details: Accurate resistance calculation is crucial for designing electrical circuits, selecting appropriate wire sizes, preventing voltage drops, and ensuring electrical safety in various applications.

4. Using the Calculator

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.

5. Frequently Asked Questions (FAQ)

Q1: What is resistivity?
A: Resistivity is an intrinsic property of a material that quantifies how strongly it opposes electric current. Different materials have different resistivity values.

Q2: How does wire thickness affect resistance?
A: Thicker wires (larger cross-sectional area) have lower resistance because there's more space for electrons to flow through.

Q3: What are typical resistivity values?
A: Copper: ~1.68×10⁻⁸ Ω·m, Aluminum: ~2.82×10⁻⁸ Ω·m, Silver: ~1.59×10⁻⁸ Ω·m (at 20°C).

Q4: Does temperature affect resistance?
A: Yes, for most metals, resistance increases with temperature due to increased atomic vibrations that impede electron flow.

Q5: When is this formula not applicable?
A: This formula applies to uniform conductors with constant cross-section. For non-uniform materials or at very high frequencies, more complex models are needed.