Question

When a copper wire is stretched, how does the resistance between its ends change?

• A. Increases
• B. Decreases
• C. Remains unchanged
• D. None of the above

Answer 1

The correct option is A

Increases

We know Resistance $R=\rho \frac{L}{A}$ where $L$ is length and $A$ is area and $\rho$ is the resistivity

The resistance of a wire is directly proportional to its length and inversely proportional to its area. A longer wire offers more resistance because electrons have to traverse a longer path. The larger the cross-sectional area, the lower the resistance since the electrons have a larger area to flow through.