What is the effect on resistance when the length of a conductor is doubled?

• A. Resistance remains the same
• B. Resistance doubles
• C. Resistance is halved
• D. Resistance is quadrupled

Answer: (B)

When the length of a conductor is doubled, the resistance also doubles. This is based on the relationship defined by Ohm's Law, which states that resistance is directly proportional to the length of the conductor. The formula for resistance (R) is given by:

R = ρ(L/A)

where ρ is the resistivity of the material, L is the length, and A is the cross-sectional area.

In this equation, if the length (L) is increased to twice its original length while the resistivity and the cross-sectional area remain constant, the resistance will increase in direct proportion to the change in length. Therefore, when you double the length of the conductor, the resistance also doubles, leading to the correct answer.

This relationship is crucial for understanding how materials behave in electrical circuits and emphasizes the significance of conductor dimensions in circuit design.