Which formula is used to calculate DC loop resistance?

• A. R = Voltage / Current
• B. R = Length / (conductivity x cross-sectional area)
• C. R = Power / Resistance
• D. R = Length x (resistivity / area)

Answer: (B)

The correct formula for calculating DC loop resistance is based on the physical properties of the conductor, specifically its length, conductivity, and cross-sectional area. This relationship captures how the resistance of a conductor is influenced by these factors.

In detail, the formula for resistance considers the length of the conductor, where longer conductors have greater resistance. Conductivity indicates how easily electric current can pass through a material, and a higher conductivity means lower resistance. Lastly, the cross-sectional area plays a critical role; a larger area allows more current to flow, thereby reducing the resistance. Thus, when you combine these elements, you arrive at the formula that relates resistance to length, conductivity, and cross-sectional area.

This understanding is key in applications such as telecommunications and electrical engineering, as it helps technicians design and troubleshoot circuits effectively. The other choices do not accurately represent the relationship necessary for calculating DC loop resistance in conductors, as they pertain to different contexts or incorrect formulations of electrical principles.