1. What is Electrical Resistance?

Electrical resistance is a measure of the opposition to the flow of electric current in a material. It depends on the material's resistivity, length, and cross-sectional area according to the formula R = ρ × L / A.

2. How Does the Calculator Work?

The calculator uses the resistance formula:

Where:

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

Explanation: Resistance increases with length and decreases with cross-sectional area. Different materials have different resistivity values.

3. Importance of Resistance Calculation

Details: Accurate resistance calculation is crucial for electrical circuit design, wire sizing, power transmission efficiency, and preventing overheating in electrical systems.

4. Using the Calculator

Tips: Enter resistivity in Ω·m, length in meters, and cross-sectional area in m². All values must be positive numbers. Common resistivity values: copper = 1.68×10⁻⁸ Ω·m, aluminum = 2.82×10⁻⁸ Ω·m.

5. Frequently Asked Questions (FAQ)

Q1: What is resistivity?
A: Resistivity is an intrinsic property of a material that quantifies how strongly it resists electric current. It's measured in ohm-meters (Ω·m).

Q2: Why does resistance increase with length?
A: Longer wires provide more obstacles for electrons to travel through, increasing the total resistance proportionally with length.

Q3: Why does resistance decrease with area?
A: Larger cross-sectional areas provide more pathways for electrons to flow, reducing resistance inversely with area.

Q4: What are typical resistivity values?
A: Conductors have low resistivity (copper: 1.68×10⁻⁸ Ω·m), insulators have high resistivity (glass: 10¹² Ω·m), semiconductors fall in between.

Q5: How does temperature affect resistance?
A: For most conductors, resistance increases with temperature due to increased atomic vibrations that impede electron flow.