Deep Dive: E3C10
The correct answer is B: UV emissions at 304 angstroms, correlated to the solar flux index. What does the 304A solar parameter measure is UV emissions at 304 angstroms, correlated to the solar flux index. 304A measures UV at 304 angstroms wavelength. For amateur radio operators, this is important for understanding solar parameters. Understanding this helps when evaluating solar activity.
Why Other Answers Are Wrong
Option A: Incorrect. Ratio of X-ray flux to radio flux isn't 304A - 304A is UV at 304 angstroms. X-ray/radio ratio isn't 304A. Option C: Incorrect. Solar wind velocity at 304 degrees isn't 304A - 304A is UV at 304 angstroms wavelength. Wind velocity isn't 304A. Option D: Incorrect. Solar emission at 304 GHz isn't 304A - 304A is UV at 304 angstroms wavelength. 304 GHz isn't 304A.
Exam Tip
304A solar parameter = UV emissions at 304 angstroms, correlated to solar flux index. Think '3'04A = '3'04 'A'ngstroms UV. 304A measures UV at 304 angstroms wavelength. Not X-ray/radio ratio, not wind velocity, not 304 GHz - just UV at 304 angstroms.
Memory Aid
304A solar parameter = UV emissions at 304 angstroms, correlated to solar flux index. Think '3'04A = '3'04 'A'ngstroms. 304A measures UV at 304 angstroms wavelength. Important for understanding solar parameters.
Real-World Example
The 304A solar parameter: It measures UV emissions at 304 angstroms (30.4 nm), which is correlated to the solar flux index. This UV measurement provides information about solar activity. This is what 304A measures - UV emissions at 304 angstroms, correlated to solar flux index.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E3C
Reference: 2024-2028 Question Pool · E3 - Radio Wave Propagation
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E3C topic.