Based on my understanding, wireless signals are lights. Why can I use my gadgets inside a room?
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Radio signal is not visible light. Radio waves can go through many solid materials because they don’t interact with non-conductive materials.
Some light can travel through and/or bounce off of objects.
Visible light can bounce (you can see things lit up by the sun without direct line of sight of the sun)
Some light, like x-rays, can penetrate through objects.
Different materials are transparent or opaque to different frequencies. For example, the metal mesh on your microwave oven door is transparent to visible light, but opaque to microwaves.
The materials which are opaque to visible light are not necessarily opaque to other wavelengths, such as radio waves.
This was a bit of mind-blown moment for me, back when I realised this. It shows how things like opaqueness and colour are not basic properties of materials, but depend on the wavelengths interacting with them.
It depends on how things interact
solid things can interact with solid things
some solid things also interact with non-solid things.
Glass and concrete are both solid enough to interact with light, think of it like glass lets most of the light through because it interacts with it a little less than concrete does.
Wireless signal is a non-solid thing, so it interacts with some solid things more than others. Air is mostly space and not very solid (dense) this means that non-solid stuff doesn’t interact with it very much at all, now if you take something like lead which is very solid, it interacts with more non-solid stuff so it won’t get through.
Most of the stuff your house may be made out of will be quite solid compared to light, but not so solid compared to stuff like radiowaves, so they can go through much easier, like it’s a window but only to radiowaves.
So imagine that different solids and liquids are like windows to different things
Wireless signals are not light. Light is a form of wireless signal though.
Both light and radio are electromagnetic waves. Different frequencies gave different properties. Visible light, microwave, xray, gamma, ultraviolet, infrared all are the same thing, radiation but with different properties resulting from the frequency and power. Essentially a energy wave from some sort either natural or man made source of power.
It depends on the technology you are using.
It’s the system design choice.
They select if they want line of sight (los ) or scatter system.
Then they select frequency and type of antenna correspondingly.
Even with same frequency of radio waves we can get los and non los communication by varying antenna design.
And radio waves are also energy carrying and they lose energy as they propagate.
The loss factor depends on frequency/wavelength of radio wave and obstacles in the path and many other things.
Eg: take GPS it is supposed to work in line of sight for great accuracy.
But in our cities that’s not possible as we need min 4 satellites for location data. So we rely on other methods since we receive those satellite signals non line of sight.
Electromagnetic waves have a wavelength, and the wavelength determines how it interacts with other objects. It the EM wave has the right wavelength, it triggers with the photo-receptors in our eyes and we see it as light. If they have a different wavelength, they will get absorbed by water molecules, making them move and heat up. This is how mirowave ovens work. Most wavelengths are either absorbed by matter or reflected by it, but if the wavelength is small enough, it will pass through certain kinds matter without interacting with it at all. This are radio waves.
The only reason things like walls are “solid,” is because they block visible light. If instead of seeing visible light, we saw radio/microwaves, walls would look transparent since the materials walls are made of don’t block electromagnetic waves of those frequencies.
>wireless signals are lights.
Yes, but a different wavelength of light. **Different materials are transparent to different wavelengths of light.**
Your wifi can pass through walls in exactly the same way that sunlight can pass through a window. That’s solid material too, right? How can light go through that? Well, you know that glass is transparent to (visible wavelength) light, right? Walls and furniture block visible light, but are transparent to radio-wavelength light in the same way.
Another related example of how we use materials being transparent to some wavelengths of light: Greenhouses work because glass is transparent to visible light, but not to infrared light (aka the heat given off by warm things). The sun shines in, passing through the glass. The light warms the things inside, which “bounce back” the light as infrared light. Except that infrared light can’t pass through glass anymore, so it bounces off the walls and is trapped inside.
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