# Where does the light go ? How it disappears ?

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This sounds so stupid but I’ve always wondered when you turn off the lights they immediately disappear (I know the light travels fast but where to ?? )
Does each light wave/particle go from its source to disappear continuously?
(The more I write the stupider it sounds sorry)

In: Physics

Every time light hits a surface and bounces off of it, some of that light gets absorbed into it. That’s actually how you can even see things, your eyes are sensitive to absorbing light.

This happens approximately a hundred million times per second in a 3 meter wide room, so even if only 1% gets absorbed in each reflection, it all gets absorbed very quickly.

A lightbulb is made of a filament which has a much higher resistance than the rest of the “grid.” High resistance is kind of like squeezing through a tube that’s way too narrow: you’re going to rub against the walls a lot.

Similarly, when electrons (the stuff that flows through the grid) go through a filament that has high resistance, they “rub” a lot and this can generate either a) heat or b) light. Both of these are forms of energy.

Lightbulb filaments have been designed to produce as much light as possible, usually while trying to keep heat as low as possible.

So that’s what happens when current is flowing. When you flip the switch, you break the circuit which means electrons are no longer flowing. Since they’re no longer moving through the filament they’re no longer “rubbing” so there’s no more light being produced.

It’s a good question, when light hits something(a wall for example) a part of it is absorbed (into heat) and a part is reflected(which is why you see the wall) when you shutoff the light it bounces around while being absorbed each time until it’s all absorbed, also this happens so fast that it’s basically instantaneous.