1. What Is Electrical Resistance?

Electrical resistance is a measure of the opposition to current flow in an electrical circuit. For copper wires, resistance depends on the wire's length, cross-sectional area, and the material's resistivity.

2. How Does The Calculator Work?

The calculator uses the resistance formula:

Where:

• \( R \) — Electrical resistance (ohms)
• \( \rho \) — Resistivity of copper = 1.68×10⁻⁸ ohm·m
• \( L \) — Length of wire = 1000 m (1 km)
• \( A \) — Cross-sectional area (m²)

Explanation: The resistance increases with longer wires and decreases with larger cross-sectional areas, following the fundamental relationship defined by the material's resistivity.

3. Importance Of Resistance Calculation

Details: Calculating wire resistance is essential for electrical engineering applications, including power transmission, circuit design, voltage drop calculations, and ensuring proper wire sizing for safety and efficiency.

4. Using The Calculator

Tips: Enter the cross-sectional area of the copper wire in square meters. The calculator will compute the resistance for a 1 km length of copper wire. Ensure the area value is positive and valid.

5. Frequently Asked Questions (FAQ)

Q1: Why is copper commonly used for electrical wiring?
A: Copper has low resistivity (1.68×10⁻⁸ ohm·m), excellent conductivity, good mechanical strength, and resistance to corrosion, making it ideal for electrical applications.

Q2: How does wire diameter affect resistance?
A: Resistance decreases with increasing wire diameter (larger cross-sectional area). Doubling the diameter reduces resistance to one-fourth due to the inverse relationship with area.

Q3: What is the effect of temperature on copper resistance?
A: Copper resistance increases with temperature. The temperature coefficient for copper is approximately 0.00393 per °C at 20°C.

Q4: How do I convert wire gauge to cross-sectional area?
A: American Wire Gauge (AWG) sizes have standardized cross-sectional areas. For example, AWG 10 wire has approximately 5.26 mm² area, while AWG 14 has about 2.08 mm².

Q5: What are typical resistance values for household wiring?
A: For standard household copper wiring (AWG 12-14), resistance is typically 1.6-5.2 ohms per kilometer, depending on the specific wire gauge and temperature.