Originally posted by flexifirm If light is part of the electromagnetic spectrum, then why is it so much different than the other parts of the EM spectrum?
Actually, in itself, visible light isn't different than the rest of the EM spectrum. Are eyes are such that we just perceive a narrow band of that spectrum and we refer to that as visible light. The only physical difference is wavelength and inversely, frequency.
Sometimes the term light is used to mean electromagnetism in general. Sometimes it's used to refer to visible light only. It depends on the context in which it is used. Ex: The speed of light in a vacuum is C(299,792,458 m/s). This applies to electromagnetism in general.
When we study EM waves... we study Light independently.
When studying EM in general, it necessarily includes visible light as well. It's not surprising that visible light is also studied independently. It's the range of EM that we were aware of first. It's the part of the spectrum that we directly perceive in a very specialized way. The field of optics is primarily concerned with the study of visible light as well as infrared and ultra-violet light.
Of course, other parts of the EM spectrum are studied independently as well. Radio, microwave, infrared, ultraviolet and x-ray EM are studied independently.
We study the refraction, diffractions, etc. of light... but there is usually no mention of refraction, diffraction, etc. of other waves.. like microwaves.
Diffraction, reflection, scattering, etc applies to all parts of the electromagnetic spectrum.
Quantum Electrodynamics is the study of electromagnetism, electrons and their interactions with each other.
A web search for micro-wave diffraction, x-ray diffraction, etc, will yield many hits.