Question

In the fabrication of an electrical extension cord, the manufacturer wants to reduce the overall resistance of the wires in the extension cord.
Which of the following changes would result in the lowest resistance?

A) decrease the diameter of the wiresB) increase the diameter of the wiresC) choose a metal wire with a larger value of resistivityD) increase the length of the extension cord

Answer 1

Answer:

Option B is correct.

Explanation:

The resistance of a material or wire is represented by the formula below.

R=(ρL)/A

where

• R is resistance of wire
• ρ is the resistivity of the material
• A is the cross sectional area of wire
• L is length of wire

Resistance increases with increase in length and resistivity which means options C and D are wrong.

A=(π$d^{2}$)/4

An increase in diameter will result in a proportional increase in area

From the resistance formula, an increase in area will cause a reduction in the resistance of the material.Thus increased diameter of wire will lower the resistance of wire. Option B is correct

Have a great day