I just noticed that we tend to call EM wavelengths shorter than

In summary, EM wavelengths shorter than visible light are often referred to as "rays" while longer wavelengths are called "waves." This terminology is based on the concept of line of sight, where light travels in straight lines and can be drawn between the source and observer. However, radio waves do not follow this same principle and instead spread out, leading to the use of transhorizon reception. Only with the use of microwave frequencies, closer to those of light, did we begin to use line of sight radio.
  • #1
jacket250
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I just noticed that we tend to call EM wavelengths shorter than visible light "rays" while we call we call those that are longer "waves". Why is that? Did we ever think that "rays" and "waves" were physically different?
 
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  • #2


Hello jacket 250 and welcome to Physics Forums.

Actually there is a difference, not between the infra and ultra EM, but between the terminology.

Perhaps you have heard the term 'line of sight'?
Well rays refer to this aspect of EM radiation. The idea that light travels in straight lines and that you can draw a straight line path between the source and observer. The whole of geometrical optics in fact.

Radio, on the other hand, 'spreads out' and transhorizon reception has long been used.
Only when we started using microwave frequencies, closer to those of light, did we start using line of sight radio.

go well
 

FAQ: I just noticed that we tend to call EM wavelengths shorter than

What is the electromagnetic spectrum?

The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. It includes all types of electromagnetic radiation, from radio waves with the longest wavelengths to gamma rays with the shortest wavelengths.

Why are some wavelengths considered "shorter" than others?

The wavelengths of electromagnetic radiation are measured in meters, and shorter wavelengths correspond to higher frequencies. This means that the higher the frequency, the shorter the wavelength. For example, visible light has a higher frequency and shorter wavelength than radio waves.

What is the relationship between wavelength and energy?

The energy of electromagnetic radiation is directly proportional to its frequency. This means that shorter wavelengths, which correspond to higher frequencies, have more energy than longer wavelengths. For example, gamma rays have higher frequencies and more energy than radio waves.

How are different types of electromagnetic radiation classified?

Electromagnetic radiation is classified by its wavelength, frequency, and energy. The categories include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

Why do we use different types of electromagnetic radiation for different purposes?

Different types of electromagnetic radiation have different properties and interact with matter in different ways. This makes them useful for different applications. For example, radio waves are used for communication, visible light is used for vision, and X-rays are used for medical imaging.

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