If 300 feet of #12 copper conductor has a resistance of 0.975 ohms, what is the resistance of 500 feet of the same conductor?

To determine the resistance of 500 feet of #12 copper conductor based on the known resistance of 300 feet, it's essential to understand that resistance is proportional to the length of the conductor. The resistance can be calculated using a simple ratio.

Given that 300 feet of the wire has a resistance of 0.975 ohms, we can establish the resistance per foot of the conductor by dividing the total resistance by the length. This gives:

0.975 ohms / 300 feet = 0.00325 ohms per foot.

Next, to find the resistance for 500 feet, multiply the resistance per foot by 500 feet:

0.00325 ohms/foot x 500 feet = 1.625 ohms.

This calculation shows that the resistance of 500 feet of #12 copper conductor would be 1.625 ohms. Thus, this is the correct answer, as it directly applies the principle of linear resistance in conductors, ensuring accuracy in scaling the known resistance to a different length.