? Where does the light go when you turn off the lamp
When a lamp is lit, it emits photons that propagate in every direction into the room and hit everything in it. These things inside the room absorb most of the photons that hit them, and they also reflect a small part of them, which helps us see things in the room.
But when the lamp is turned off, the production of new photons stops, and the existing ones inside the room are reflected and scattered between different objects an infinite number of times until they are completely absorbed.
If you had paid attention in high school science class while the professor was explaining the basics of photonics, you would know by now that light is made up of millions of tiny particles; so small that it is impossible for the naked eye to see; Known as photons.
They are the fundamental particles that transmit every form of electromagnetic radiation including radio waves, ultraviolet rays, microwaves, and of course; Visible light too.
When you go into a dark room and turn on the lamp, the light sweeps through the room, and more specifically, the room is filled with billions of photons, which allows us to see what's inside the room.
Except when you turn off the room lamp, where does all that light go? What happens to the billions of photons in a room? Do you die
? and cease to exist
Before answering this question, let's do a little review: You may already know that visible light is a type of electromagnetic radiation and forms a small part of the electromagnetic light chain; Same group as radio waves, ultraviolet rays, gamma rays, etc.
The photon is the essential molecule for any kind of electromagnetic radiation, whether it's the radio waves that transmit the Wi-Fi signal in your home, the microwaves that heat food in your oven, or the visible light that helps us see the world around us.
Without stopping, the photon moves at an astonishing speed of 300,000 kilometers per second in a vacuum; Note that the speed of photons is the same as the speed of light.
? How do photons light things up
based light source; A lamp, for example, inside a room emits millions of photons that spread in all directions, and since the lamp is inside the room, i.e. inside a closed space, the photons emitted from it hit everything that gets in its way, and from it they light up everything inside the room.
Here's a cute animation that explains how a group of photons lights up an enclosed space:
Believe it or not: the camera's lenses were able to spot light as it moved.
Note: The above gif was taken from a TED Talk by Ramesh Raskar; A professor at the Massachusetts Institute of Technology, who talked about the “Femto” imaging technology (an imaging technology that takes a trillion pictures per second, and from it has the ability to photograph light as it moves).
So where do the photons go when the light source is gone or the
? lamp is off
As long as the lamp is lit, the room has a continuous supply of photons.
Some are absorbed by the endless photons that hit the objects; A table, for example, is inside a room while others bounce many times, and lose a significant amount of their energy in the process.
These reflected photons keep hitting everything that stands in their way, and each time they lose part of their energy until they are completely absorbed by an object or object inside the room.
The room is always lit as long as the lamp is on
In this way, the room is always lit as long as the lamp is lit, and at the moment it is turned off; Things change very quickly, at the speed of light.
The photons that are emitted while the lamp is lit continue to dance between surrounding objects until they are absorbed, which happens within a millisecond.
But if the lamp is still lit, the rapid absorption of these photons will not make any difference, because the lamp is constantly producing new photons in the room, but if it is turned off, the last photons emitted from it are absorbed by the surrounding objects, and the energy is used in these absorbed photons In heating these things in a very small amount is completely unnoticed, because as we know, all this happens at the speed of light, precisely in about a millionth of a second, which is faster than we humans can observe or even notice, and that is why the room is plunged into complete darkness in The moment the lamp goes out.
Stunningly, what follows turning off a lamp in outer space is different from what follows here in a room on Earth, because unlike an ordinary room, the photons in space remain moving and traveling endlessly in the vast void of space without hitting anything for a long period of time.
Source: scienceabc . website
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