Deep Dive: T3B11
The correct answer is B: 300,000,000 meters per second. The approximate velocity of a radio wave in free space is 300,000,000 meters per second (3 × 10^8 m/s), which is the speed of light. This is a fundamental constant. All electromagnetic waves, including radio waves, travel at the speed of light in free space. This speed is approximately 300 million meters per second, or 186,000 miles per second. It's the same for all radio frequencies - whether you're transmitting on 2 meters, 20 meters, or any other frequency, the wave travels at this same speed. This constant speed is what makes the wavelength-frequency relationship work.
Why Other Answers Are Wrong
Option A: Incorrect. 150,000 m/s is way too slow. That's less than the speed of sound. Radio waves travel at the speed of light. Option C: Incorrect. 300,000,000 miles per hour is wrong units. The speed is 300,000,000 meters per second, not miles per hour. Option D: Incorrect. 150,000 miles per hour is far too slow. Radio waves travel at 186,000 miles per second (not per hour), which equals 300,000,000 m/s.
Exam Tip
Radio wave speed = 300,000,000 m/s. Remember: Radio waves travel at approximately 300,000,000 meters per second (speed of light) in free space. This is a key constant to memorize.
Memory Aid
**R**adio **S**peed = **3**00 **M**illion **M**eters/**S**econd (think 'RS = 300 MMS' = 300 Million Meters/Second)
Real-World Example
You transmit a signal, and it travels through space at 300,000,000 meters per second. In just one second, your signal travels 300,000 kilometers (186,000 miles). This incredible speed is why radio communications can span the globe almost instantly. Whether you're on 2 meters or 20 meters, your signal travels at this same speed.
Source & Coverage
Question Pool: 2022-2026 Question Pool
Subelement: T3B
Reference: FCC Part 97.3
Key Concepts
Verified Content
Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T3B topic.