What property of a radio wave defines its polarization?
The correct answer is A: The orientation of the electric field. The polarization of a radio wave is defined by the orientation of the electric field. If the electric field is vertical, the wave is vertically polarized. If the electric field is horizontal, the wave is horizontally polarized.
The polarization is determined by how the transmitting antenna is oriented, which determines the orientation of the electric field in the radiated wave. A vertical antenna produces a vertically polarized wave (electric field vertical). A horizontal antenna produces a horizontally polarized wave (electric field horizontal). The magnetic field is always perpendicular to the electric field, so once you know the electric field orientation, the magnetic field orientation is determined.
Exam Tip
Polarization = Electric field orientation. Remember: Wave polarization is defined by the orientation of the electric field. Vertical E-field = vertical polarization, horizontal E-field = horizontal polarization.
Memory Aid
"**P**olarization = **P**rimary **E**lectric (think 'P = PE' = Primary Electric field orientation)"
Real-World Application
You're using a vertical antenna on 2 meters. This antenna produces a vertically polarized wave - the electric field oscillates vertically. When you switch to a horizontal antenna, the wave becomes horizontally polarized - the electric field oscillates horizontally. The polarization follows the electric field orientation, which follows the antenna orientation.
FCC Part 97.3Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. While the magnetic field is related, polarization is specifically defined by the electric field orientation, not the magnetic field.
Option C: Incorrect. The ratio of magnetic to electric field energy doesn't define polarization. Polarization is about orientation, not energy ratios.
Option D: Incorrect. The ratio of velocity to wavelength doesn't define polarization. That's related to frequency, not polarization.
题目解析
The correct answer is A: The orientation of the electric field. The polarization of a radio wave is defined by the orientation of the electric field. If the electric field is vertical, the wave is vertically polarized. If the electric field is horizontal, the wave is horizontally polarized. The polarization is determined by how the transmitting antenna is oriented, which determines the orientation of the electric field in the radiated wave. A vertical antenna produces a vertically polarized wave (electric field vertical). A horizontal antenna produces a horizontally polarized wave (electric field horizontal). The magnetic field is always perpendicular to the electric field, so once you know the electric field orientation, the magnetic field orientation is determined.
考试技巧
Polarization = Electric field orientation. Remember: Wave polarization is defined by the orientation of the electric field. Vertical E-field = vertical polarization, horizontal E-field = horizontal polarization.
记忆口诀
**P**olarization = **P**rimary **E**lectric (think 'P = PE' = Primary Electric field orientation)
实际应用示例
You're using a vertical antenna on 2 meters. This antenna produces a vertically polarized wave - the electric field oscillates vertically. When you switch to a horizontal antenna, the wave becomes horizontally polarized - the electric field oscillates horizontally. The polarization follows the electric field orientation, which follows the antenna orientation.
错误选项分析
Option B: Incorrect. While the magnetic field is related, polarization is specifically defined by the electric field orientation, not the magnetic field. Option C: Incorrect. The ratio of magnetic to electric field energy doesn't define polarization. Polarization is about orientation, not energy ratios. Option D: Incorrect. The ratio of velocity to wavelength doesn't define polarization. That's related to frequency, not polarization.
知识点
Polarization, Electric field, Antenna orientation, Radio waves
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.