Based on my understanding, wireless signals are lights. Why can I use my gadgets inside a room?
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>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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