What is Visible light: Definition and 100 Discussions

Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). This wavelength means a frequency range of roughly 430–750 terahertz (THz).

The primary properties of visible light are intensity, propagation-direction, frequency or wavelength spectrum and polarization. Its speed in a vacuum, 299 792 458 metres a second (m/s), is one of the fundamental constants of nature, as with all types of electromagnetic radiation (EMR), light is found in experimental conditions to always move at this speed in a vacuum.In physics, the term 'light' sometimes refers to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. Like all types of electromagnetic radiation, visible light propagates as waves. However, the energy imparted by the waves is absorbed at single locations the way particles are absorbed. The absorbed energy of the electromagnetic waves is called a photon and represents the quanta of light. When a wave of light is transformed and absorbed as a photon, the energy of the wave instantly collapses to a single location and this location is where the photon "arrives". This is what is called the wave function collapse. This dual wave-like and particle-like nature of light is known as the wave–particle duality. The study of light, known as optics, is an important research area in modern physics.
The main source of light on Earth is the Sun. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight.

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  1. P

    Force of Electromagnetic Radiation and Visible Light

    Is there an equation for force due to electromagnetic radiation? For example, is there a force due to orange light?
  2. C

    Is long distance visible light transmission possible?

    Is long distance "visible light" transmission possible? Hi Lets say i need to transmit a lot of visible light from one place to another. Is this possible to do on long (50~100 miles) distance?
  3. S

    Transmitting visible light via optical fiber

    Hi, A colleague of mine at work has this idea of using a focusing lens to focus the visible light into a optical fiber and guide it to some destination, e.g. room with no windows. I have no experience in optics, or in QED (only some "layman" knowledge of monochromatic light and its...
  4. C

    Inelastic scattering of visible light in graphene

    Inelastic scattering of Xray photons from electrons give them a wavelength shift, the Compton effect. The shift is inverse proportional with the mass of the electron. Now, if visible light scatters inelastic from electrons in graphene what will be the wavelength shift? The electrons in graphene...
  5. A

    How can we see visible light since electric and magnetic fields are invisible?

    what do we mean exactly by visible light? Since light is oscillating electric and magnetic fields, and both electric and magnetic fields are invisible, what do we actually see? is color the wave itself?when we see colors do we see the waves themselves and if their wavelength were bigger would...
  6. H

    Limits of Human Vision: Visible Spectrum and Beyond

    I got this thing from wikipedia: http://img72.imageshack.us/img72/9878/vlszo.jpg Link to wikipedia: Visible spectrum So: - Is it the right scan of visible spectrum? Because when I search, there are a lots of other version, which is not really like each other. (Google Link) - What is the...
  7. H

    Splitting infrared and visible light.

    Hi all, is there an efficient way of splitting both of these waves of sunlight?? I've came across http://coolcosmos.ipac.caltech.edu/cosmic_classroom/classroom_activities/herschel_example.html and thought of an idea of using a prism. But, do you think that is is efficient? ( I'm going to use...
  8. C

    Exploring the Bohr Model: Visible Light Transitions in Li++

    Bohr Model [b]1. Assuming that the wavelengths of visible light lie between about 300nm and 700nm, what transitions in Li++ (hydrogenic lithium ions, Z=3) would be visible. Identify each transition by initial and final principal quantum number n. Also identify those transitions that are also...
  9. C

    Visible Light Transitions in Li++ (Z=3)

    [b]1. Assuming that the wavelengths of visible light lie between about 300nm and 700nm, what transitions in Li++ (hydrogenic lithium ions, Z=3) would be visible. Identify each transition by initial and final principal quantum number n. Also identify those transitions that are also seen in...
  10. P

    Why is Glass Opaque to IR and UV, But Not Visible Light?

    According to my understand of what makes something transparent, it's because a given wavelength of light doesn't have sufficient energy to raise the electrons in a material to a higher energy level, so the photons are not absorbed and continue on. This explains why glass is transparent for...
  11. S

    How Does Colored Light Affect Water Temperature?

    Hey guys, it is possible that to observe the energy outcome of visible light? By adding colored frame in front of the light source and shined on a beaker with water Using data logger to record the data, how long should I take the experiment? Thanks for helping
  12. V

    Is there plasma that doesn't radiate visible light? I think the

    Is there plasma that doesn't radiate visible light? I think the electrons falling back to the nucleus radiate visible photons. But what if the plasma only has particles that are not atoms?
  13. T

    How is white light made up of all the colours in visible light?

    In a light bulb, is the filament made up of elements which each produce a colour of visible light to make white?
  14. T

    Exploring the Differences: Infrared vs. Visible Light Photography

    Hi .. May i ask why does a infrared photograph of a person look different from a photograph taken from visible light ? Relevant Equations : V = ƒ x lambda I believe it has got to do with the wavelength or frequency. However, i can't explain it ..
  15. L

    Can visible light excite electrons?

    If so, then that means they can cause things to warm up right?
  16. C

    Exploring the Possibility of Visible Light from an Oscillator

    If an oscillator were to ever reach the visible spectrum, would an antenna connected with the oscillator output generate light?
  17. L

    If something emits visible light

    Will it emit all frequencies lower than visible light? For example, a candle will emit all radiation, but no higher than visible light.
  18. M

    When the electrons in silicon are excited by visible light and jump

    When the electrons in silicon are excited by visible light and jump into the conduction band how do the electrons replace? So for example, wouldn't a solar cell only last for so long if all the valence electrons are excited and converted into current. I am looking at it as if all the valence...
  19. R

    Visible Light Communication

    A colleague and I are in our 4th year of Electrical Engineering and are designing a Visible Light Communication device capable of sending text, pictures, videos, etc over a binary light channel. We are currently using an FTDI chip to interface between the USB and receiver/transmitter. According...
  20. A

    How come there is visible light in Uv lights?

    Hi! I did a laboration on detecting different wavelenght from a UV-c light tube and the electrometer detected some activity from the Monochromator in the area of visible light (400nm-700nm). I would like to know if this has something to do with the quality of the light tube? Or does something...
  21. M

    Visible light Absorption Spectra vs Color of mineral

    I have been wondering how to realize the color of a mineral by having the absorption Spectra... The following case is an example; The image is the absorption spectra of a Bolivian Amethyst which looks like this; [PLAIN]http://www.tequilabay.com/amethyst300lbbolivian.jpg I have tried...
  22. S

    What Happens to Starlight When Traveling Faster Than Light?

    If, for argument sake, you had a spaceship that could go thousands of times the speed of light what would happen to the electromagnetic radiation being emitted from the stars you head towards and away from? Would the stars that you are traveling towards get duller and duller the faster you go...
  23. P

    Visible Light: Beyond 400-800nm?

    In spectrum of EM radiation domain of visible light isn't strictly limited. In books is usually given from 400-800nm. But for visible domain short-wave limit is \lambda=430nm, and long-wave limit is \lambda=690nm? Why we say then that the boundaries are 400-800nm?
  24. T

    Changing Visible Light into IR and then back

    Is there a way to change visible light like the light coming out of the screen you're reading into infrared or any other invisible light and then take that and change it back somewhere else? What I'm what I'm trying to do is make a computer screen or maybe a T.V screen visible to only those who...
  25. N

    Energy <-> Mass conversion and visible light

    Energy <---> Mass conversion and visible light We are all familiar with the following concept: E = MC2 and M = E / C2 My question goes as follows, theoretically speaking, if at my disposal is adequate amount of energy to convert that energy into a mass of 6×1024 KG, what is the length...
  26. K

    Material that blocks visible light but not uv light

    is it possible to have a material block high wavelength waves but not low length waves? Gamma rays can pass through objects that visible light cannot. Any thoughts? I was thinking a certain bandgap?
  27. J

    Color and visible light in general

    I'm trying to get a better understanding of color and visible light in general and see how every single visible color is formed. Does this sound right? The sun sends us white light which is a mixture of all the monochromatic colors that our eyes are sensitive to and when we mix both sides of...
  28. E

    Calculating Visible Light Photons Emitted Per Second & Distance

    a.) If the average frequency emitted by a 200 W light bulb is 5x10^14, and 10.0% of the input power is emitted as visible light, approximately how many visible-light photons are emitted per second? I solved this part of the problem by finding the energy (E = hf) and dividing 10% of 200W by...
  29. J

    Question about visible light properties.

    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...
  30. P

    Creating visible light using an antenna

    If you could get a circuit to oscillate quickly enough, could visible light be produced using a simple metallic antenna?
  31. S

    Visible light and wavelengths

    Homework Statement Ok I have two questions. 1. Light waves of which wavelength will destructively interfere due to the thickness of the bubble film? The bubble film thickness is 165 nm, with an index of refraction of n = 1.3. a= 430 nm b= 650 nm c= 860 nm d= 285 nm 2. You are...
  32. Z

    Uncertainty propagation visible light spectrum

    Homework Statement I have conducted an experiment which attempts to calculate the range of the visible light spectrum. Basically white light was shined through a diffraction grating (300 lines/mm) and diffraction theory is applied to calculate the wavelength. So, here are the variables...
  33. S

    Why is visible light invisible?

    Please take a look at this link http://www.warpedspace.org/lightingT/Images/LightProperties/LightReflection.jpg My question is: why can we see the blue floor but not the incident and reflected rays of light?
  34. M

    Fundamental reasoning:Electromagnetic Wave - Visible Light

    The filament of a bulb when it gets heated to some threshold level generates the visible light. My query: 1. Why is it called electromagnetic then? Here, if i understand correctly, the waves are produced by the energy emitted by the transition of the electrons between various orbits of the...
  35. M

    Why Are Visible Light Waves So Puny?

    This is purely a question I know little or nothing about light and the whole EM spectrum for that matter I was just wondering something. Why are visible light waves so puny compared to other frequencies on the EM spectrum. What I mean is that I can send a pulse to an antenna and emit let's say...
  36. M

    Burning Elements - Visible Light Spectrum

    We did a chemistry experiment were we burned different metal chlorides on the bunsen to observe the different flame colors produced. Anyhow I'm writing up the report but there's one thing I'm not sure about. I can't make any mistakes because I made the mistake of displaying way too much...
  37. thenewmans

    How fast must a magnet go to make visible light?

    If I get this whole “Moving magnet and conductor problem” business at all, one frame’s electricity is another frame’s EM wave. So moving a magnet causes an electromagnetic wave, AKA: photon. I assume the faster you move it, the higher the energy of that wave/photon. (Maybe you have to vibrate it...
  38. G

    Visible Light: Wavelength & Frequency

    What property of visible light defines its color, the wavelength or frequency (or something else)?
  39. M

    Exploring the Unknown: Modulating Light for Deeper Visibility

    I am aware that the reason we cannot see things around the size of atoms is due to the fact that the wavelength of light is too great. My question is why can you not modulate light, as you do with FM radios, to a higher frequency and therefore a shorter wavelength? Would that not enable you to...
  40. C

    Why Does UV Light Cause Sunburn But Visible Light Does Not?

    Homework Statement UV light causes sunburn, whereas visible light does not. Explain. Homework Equations N/A The Attempt at a Solution I'm guessing that it might have sinething to do with the electromagnetic spectrum.
  41. F

    What are the amplitudes called for blue visible light, and microwaves?

    The amplitude of sound waves is commonly referred to as volume. What about for blue visible light, and microwaves? I'm guessing for the first one it's brightness. Btw I'm looking for a word answer, not the magnitude of the amplitude (not a numerical amplitude) Thanks for reading.
  42. P

    Why can visible light pass among glass? Why glass is is transparent to visible light?

    Why can visible light pass among glass? Why glass is is transparent to visible light?
  43. J

    Wavelength of visible light under a oil leak

    A disabled tanker leaks kerosene (n=1.2) into the Persian Gulf, creating a large slick on the top of water (n=1.3). If you are scuba diving directly under the region of the slick, whose thickness is 460nm, while the Sun is overhead, for which wavelength(s) of visible light is the transmitted...
  44. B

    Exploring the Challenges of Using Visible Light for Radio Transmission

    Homework Statement Why can't you make radio transmitter that transmits visible light instead in the same way we transmith AM signals? Homework Equations The Attempt at a Solution Im thinking maybe they would not be very effective as their wavelenth is so small, they would die...
  45. T

    Visible Light Reflection from Oil-Water Interface in Parking Lot

    A tiny layer of oil (n = 1.25) is situated on top of a water puddle (n = 1.33) in a parking lot. If the thickness of the oil is 242 nm, the what color(s) of visible light will give a strong reflection? 2t=m*lambda/n2 2t=242nm/1.25 and then 2t=242nm/1.33 i just don't know what goes where...
  46. U

    Compton effect and visible light

    why is it extremely dificult to observe the compton effect using visible light? is it because visible light does not have a short enough wavelenght to excite the electrons?
  47. E

    Why can wireless internet signals pass through walls when visible light cannot?

    Hi, the title above is a specific instance of a more general question. I'm basically wondering why the atoms in a wall would prevent visible light from passing through, yet allow both X-rays (which are HIGHER frequency) and radio waves such as 802.11b wireless internet (which are LOWER...
  48. S

    Can a Silver Oxide Coating Start a Fire with Sunlight?

    I've seen those filters for cameras (etc.) which look black (because they don't pass almost no visible light), but they allow infrared light to go right thorough it. What is it made of? (i tried to find out on my own using google; I tried to find out what elements absorb what wavelenghts, but...
  49. N

    What is the range of wavelengths for visible light?

    Wavelenght of Visible Light? is it 400nm to 800nm or is it 450nm to 750nm thanks nautica
  50. Rockazella

    Visible light is an EM wave just like radio waves are

    Im not sure of this, but visible light is an EM wave just like radio waves are, right? If I am right, does that mean mirrors reflect all ranges of EM waves, radio included? Also what is it about a mirror that reflects photons?
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