Question about visible light properties.

In summary, light is only visible if it is either directly emitted or reflected by a source, as it travels in a straight line and does not emit or reflect photons. This is why we cannot see light passing from one point to another, unless it meets our eyes.
  • #1
JSEverex
3
0
Why are we unable to see light except if we are looking at the light source or a source that is reflecting the light?

For example; say we set up a powerful laser but we cannot see the origin or the end point. The a vacuum is produced in the room to remove all possible particles that might reflect the laser's light. We switch the laser on but we cannot see the beam of light passing from one point to the other.

You can't really say that its because the particles are so small because if you take into account a lightsource like the sun, the light radiation and packets of quanta pretty much saturate anything in direct lines from the source (or anything reflecting the source).

So I guess the more appropriate question is why can't we quanta in transit?
 
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  • #2
JSEverex said:
Why are we unable to see light except if we are looking at the light source or a source that is reflecting the light?
It's because light travels in a straight line.
 
  • #3
You may be thinking of how we can see ordinary particles when they are on the move. That is becasue ordinary particles reflect or emit light i.e. photons.

Photons do not reflect or emit photons.
 
  • #4
As has been pointed out, becase light goes in a straight line and if the laser is pointed at a wall (and the wall is not reflected) and there is no dust or such to scatter the light in all directons then not a single photon MEETS OUR EYE. And we see things when photons his our eyes.
 
  • #5
Okay I get it. I feel a bit dumb. Photons don't emit light, they are the light, so we don't see it unless the photon hits our eyes, I get it.
 
  • #6
JSEverex said:
Okay I get it. I feel a bit dumb. Photons don't emit light, they are the light, so we don't see it unless the photon hits our eyes, I get it.
Don't feel dumb. Having someone get a question answered to their satisfaction is a very rare and gratifying thing for many of us. Ask more!
 

1. What is visible light?

Visible light is a form of electromagnetic radiation that is visible to the human eye. It is a part of the electromagnetic spectrum that includes other types of radiation such as radio waves, microwaves, and X-rays.

2. What are the properties of visible light?

The properties of visible light include wavelength, frequency, and energy. Visible light has a wavelength range of approximately 400-700 nanometers, a frequency range of 430-750 THz, and an energy range of 1.65-3.26 eV.

3. How does visible light interact with matter?

Visible light can interact with matter in three ways: absorption, reflection, and transmission. When light is absorbed, it is converted into a different form of energy, such as heat. When light is reflected, it bounces off the surface of an object. When light is transmitted, it passes through an object without being absorbed or reflected.

4. How does the color of visible light affect its properties?

The color of visible light is determined by its wavelength. Each color has a different wavelength and therefore has different properties. For example, red light has a longer wavelength and lower frequency than blue light, making it less energetic.

5. What are some practical uses of visible light?

Visible light has many practical uses in our daily lives. It is used in photography, communication technology (such as fiber optics), and in medical imaging. It also plays a crucial role in photosynthesis, the process by which plants convert light energy into chemical energy.

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