安裝中文字典英文字典辭典工具!
安裝中文字典英文字典辭典工具!
|
- Electromagnetism | Definition, Equations, Facts | Britannica
Examples of electromagnetic waves traveling through space independent of matter are radio and television waves, microwaves, infrared rays, visible light, ultraviolet light, X-rays, and gamma rays All of these waves travel at the same speed—namely, the velocity of light (roughly 300,000 kilometres, or 186,000 miles, per second)
- Introduction to the Electromagnetic Spectrum - NASA Science
Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays The human eye can only detect only a small portion of this spectrum called visible light A radio detects a different portion of the spectrum, and an x-ray machine uses yet another portion
|
|
|