Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E5D
E5D10E5D

As a conductor’s diameter increases, what is the effect on its electrical length?

Deep Dive: E5D10

The correct answer is D: It increases. As a conductor's diameter increases, what is the effect on its electrical length is that it increases. Larger diameter conductors have longer electrical length due to reduced velocity factor. For amateur radio operators, this is important for antenna design. Understanding this helps when designing antennas.

Why Other Answers Are Wrong

Option A: Incorrect. Thickness has no effect isn't correct - larger diameter increases electrical length. No effect is wrong. Option B: Incorrect. It varies randomly isn't correct - larger diameter increases electrical length. Random variation is wrong. Option C: Incorrect. It decreases isn't correct - larger diameter increases electrical length. Decrease is wrong.

Exam Tip

Conductor diameter increase = electrical length increases. Think 'D'iameter 'I'ncrease = 'D'ifferent 'I'nductance (longer electrical length). Larger diameter conductors have longer electrical length due to reduced velocity factor. Not no effect, not random, not decrease - just increases.

Memory Aid

Conductor diameter increase = electrical length increases. Think 'D'iameter 'I'ncrease = 'I'ncreased electrical length. Larger diameter conductors have longer electrical length due to reduced velocity factor. Important for antenna design.

Real-World Example

As a conductor's diameter increases: The effect on its electrical length is that it increases. Larger diameter conductors have reduced velocity factor, making them electrically longer for the same physical length. This is the effect - electrical length increases.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E5D

Reference: 2024-2028 Question Pool · E5 - Electrical Principles

Key Concepts

Conductor diameter increases Effect on electrical length It increases Electrical length

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E5D topic.