Factors influencing the resistance of a wire conductor

1. What is Resistance?

• Resistance $(R)$ is the opposition to the flow of electric current in a conductor.

• It is measured in Ohms $(Ω).$

• Formula: where: $R = \frac{V}{I}$

  • $R =$ Resistance $(Ω)$
  • $V =$ Potential difference $(V)$
  • $I =$ Current $(A)$

2. Factors Affecting Resistance

a) Length of the Wire

✔ Longer wires have greater resistance.

✔ More distance for electrons to travel → more collisions → higher resistance.

b) Thickness (Diameter) of the Wire

✔ Thinner wires have higher resistance.

✔ Less space for electrons → more collisions → increased resistance.

c) Temperature of the Wire

✔ Higher temperatures increase resistance.

✔ Atoms vibrate more at higher temperatures → more electron collisions → greater resistance.

d) Type of Material

✔ Different materials have different resistances.

✔ Good conductors (e.g., copper) have low resistance.

✔ Poor conductors (e.g., tungsten) have high resistance.

3. Key Takeaways

✔ Longer, thinner, and hotter wires have more resistance.

✔ Material choice affects resistance.

✔ Copper is a better conductor than tungsten.

Exam Tip

💡 When asked to explain resistance, always consider length, thickness, temperature, and material type!