Which of the following represents the relationship between resistance, resistivity, and length?

• A. R = p / l
• B. R = p + l
• C. R = p - l
• D. R = p x l

Answer: (D)

The correct representation of the relationship between resistance, resistivity, and length is given by the formula R = ρ × (L/A), where R is resistance, ρ (rho) is resistivity, L is the length of the conductor, and A is the cross-sectional area.

In this context, it's important to understand that resistance is directly proportional to the length of the conductor and the resistivity of the material. As the length of the conductor increases, the resistance also increases, and higher resistivity materials have higher resistance as well. However, the option that states R = ρ × l refers to the relationship where the area (A) is implicit or constant, focusing on length and resistivity.

The other options provided do not accurately represent the relationship as they suggest operations (addition, subtraction, division) that do not apply to the relationship between these electrical parameters. Therefore, the correct formulation captures the idea that resistance increases with both material resistivity and the length of the conductor, fitting within the larger context of electrical principles.