What are circularly polarized electromagnetic waves?
The correct answer is B: Waves with rotating electric and magnetic fields. What are circularly polarized electromagnetic waves is waves with rotating electric and magnetic fields. Circular polarization means the fields rotate as the wave propagates. For amateur radio operators, this is important for understanding polarization. Understanding this helps when working with antennas.
Exam Tip
Circularly polarized waves = waves with rotating electric and magnetic fields. Think 'C'ircularly 'P'olarized = 'C'ircular 'P'attern (rotating fields). Circular polarization means the fields rotate as the wave propagates. Not bent shape, not circling Earth, not loop antenna - just rotating fields.
Memory Aid
"Circularly polarized waves = waves with rotating electric and magnetic fields. Think 'C'ircularly 'P'olarized = 'R'otating fields. Circular polarization means the fields rotate as the wave propagates. Important for understanding polarization."
Real-World Application
Circularly polarized electromagnetic waves: They have rotating electric and magnetic fields. As the wave propagates, the electric and magnetic field vectors rotate in a circular pattern. This is different from linear polarization where fields don't rotate. This is what circularly polarized waves are - waves with rotating fields.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Electric field bent into circular shape isn't circular polarization - circular polarization means rotating fields. Bent shape isn't polarization.
Option C: Incorrect. Waves that circle Earth isn't circular polarization - circular polarization means rotating fields. Circling Earth isn't polarization.
Option D: Incorrect. Waves produced by loop antenna isn't the definition - circular polarization means rotating fields. Loop antenna isn't the definition.
题目解析
The correct answer is B: Waves with rotating electric and magnetic fields. What are circularly polarized electromagnetic waves is waves with rotating electric and magnetic fields. Circular polarization means the fields rotate as the wave propagates. For amateur radio operators, this is important for understanding polarization. Understanding this helps when working with antennas.
考试技巧
Circularly polarized waves = waves with rotating electric and magnetic fields. Think 'C'ircularly 'P'olarized = 'C'ircular 'P'attern (rotating fields). Circular polarization means the fields rotate as the wave propagates. Not bent shape, not circling Earth, not loop antenna - just rotating fields.
记忆口诀
Circularly polarized waves = waves with rotating electric and magnetic fields. Think 'C'ircularly 'P'olarized = 'R'otating fields. Circular polarization means the fields rotate as the wave propagates. Important for understanding polarization.
实际应用示例
Circularly polarized electromagnetic waves: They have rotating electric and magnetic fields. As the wave propagates, the electric and magnetic field vectors rotate in a circular pattern. This is different from linear polarization where fields don't rotate. This is what circularly polarized waves are - waves with rotating fields.
错误选项分析
Option A: Incorrect. Electric field bent into circular shape isn't circular polarization - circular polarization means rotating fields. Bent shape isn't polarization. Option C: Incorrect. Waves that circle Earth isn't circular polarization - circular polarization means rotating fields. Circling Earth isn't polarization. Option D: Incorrect. Waves produced by loop antenna isn't the definition - circular polarization means rotating fields. Loop antenna isn't the definition.
知识点
Circularly polarized electromagnetic waves, Rotating electric and magnetic fields, Circular polarization, Field rotation
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.