Visible Light Spectrum

Join us here to ask and answer questions on the "illuminating" topic of the visible light spectrum. This includes questions about: refraction, reflection, rainbows, prisms, mixing colored lights, and the spectrum of colors that make up white light.

4,306 Questions
Speed of Light
Visible Light Spectrum

Does x ray travel faster than visible light?

X-rays travel at the same speed as visible light. All frequencies of electro-magnetic radiation (of which light is a very narrow band) travel at the speed of light (C) in a vacuum: 299,792,458 meters per second.

The speed of light varies in different medium. Given an angle of incidence other than 90 or 0, the wave will shift direction an amount determined by its frequency. The higher the frequency, the greater the shift. The transition between two medium of different refractive indices causes a variation in the phase velocity of the wave, but does not affect its frequency.

Visible Light Spectrum

Does a UV wavelength of 395-410 nm work as an black light?

Yes, a "black light" is an ultraviolet light with wavelength of about 395-410 nm.

Visible Light Spectrum

When white light passes through a prism which will be bent more the red or the green light and explain why?

In white light various colors of light are mixed together, primarily blue yellow and red. When white light in air passes through a glass prism having a certain refractive index, all the differently colored lights have the same angle of incidence (θ) but each differently colored light has a different emergent angle of refraction, going from red light (at the minimum angle) to blue light (having the maximum angle).

According to the refractive index formula n = sin θsin γ, where n is the refractive index of the prism, sin θ is the sine of the angle of incidence (θ) and sin γ is the sine of the angle of refraction (γ).

I believe that is just a different way of describing the effect, not an explanation. Red light in glass travels at a lower speed than in air or vacuum. So when a wavefront hits a flat surface of glass at an angle, the end of the wave front inside the glass travels more slowly than the part of the wavefront that has not yet entered the glass. But the wave front must still be continuous all along its length, and the only way to achieve that is if the wavefront inside the glass proceeds in a tilted direction. The slower the light in the glass, the bigger the change in angle. Green light in glass travels faster than red and slower than blue. So the different colors are spread into different angles of refraction.

Visible Light Spectrum

What are some bright things?

Bioluminous things include glow worms, the sun, stars, the moon, fire.

Non luminous things include books, tables, contrasticly painted street signs, light wear, bright orange rooms, bright yellow rooms.

Luminous things include Light bulbs, lamps, cell phone screens, computer screens, tv screens, las vegas, light - up sreet billboards, street lamps, stoplights, car headlights, car taillights, flashlights, bicycle lights, candles, iPads, iPod nanos.

Visible Light Spectrum

What colors does the rainbow have?

The rainbow consists of the visible spectrum ranging from red, orange, yellow, green, blue, indigo, and violet.


Answer #2:

The rainbow has ALL of the colors. Every shade of paint that was ever

mixed, every hue of fabric ever dyed, every highlight of hair, every color

that any human eye ever saw or is able to see, they're all in the rainbow.

Many have names, but most don't.

Electromagnetic Radiation
Visible Light Spectrum

Who discovered the visible spectrum of light?

Isaac Newton discovered the visible spectrum of light while fooling around with a prism (from which is derived the basic principle of a rainbow.) He later wrote about his findings in his well-known book, Optiks. Isaac Newton was also a master of atsronomy, calculus, and physics. It was also he who "discovered" gravity when an apple fell on his head. It is also probable that this experience led him to discover the effect of concussions on dementia. OK, not really about the dementia part.

Sun Tanning
Visible Light Spectrum

Do the sun's tanning rays penetrate water and to what degree?

All the sun's rays penetrate water, but each color penetrates to a different depth. The colors at the upper end of the light spectrum, especially the UV (ultraviolet) that causes tanning, penetrate deepest. The UV portion of the sun's light can penetrate into clear water for a hundred feet or more at midday. The safest way to avoid overexposure is to remember that if you can see the sunlight, it may cause sunburn, and to limit exposure accordingly or perhaps wear a T-shirt or wet-suit.

Visible Light Spectrum

Is visible light made of seven colors?

There are 7 main colours but are normally the 7 colours that are always used.







7.Violet (not called purple because that's the way it is in this case)

To remember all there colours easily with the Acronym (ROY G. BIV)

Visible Light Spectrum

What is the duality of light?

If you are referring to the wave-particle duality of light, it is a theory Albert Einstein came up with. The way light acted really confused scientists. Light sometimes acts like a wave, and sometimes acts like a bunch of particles. Albert Einstein ran a multitude of tests. After all of his tests he came to the conclusion that light is unique in that sometimes it can act like a wave, and sometimes it can act like particles.

Visible Light Spectrum

Does infrared radiation have a higher frequency than visible light?

No, infrared radiation (IR) does not have a higher frequency than visible light. Visible light is above IR on the electromagnetic spectrum. It (visible light) has higher frequency and shorter wavelengths than IR radiation does.

History of Science
Visible Light Spectrum

How is visible light made?

Light is emitted when an electron drops from the orbit of an excited state, into its natural state.

The quantum of light emitted is characteristic of the change in energy of the two electron states, and also of the actual element involved.

Visible Light Spectrum

Where can tritium light sources be acquired?

Tritium lighting is made using glass tubes with a phosphor layer in them and tritium (a hydrogen isotope) gas inside the tube. Such a tube is known as a "gaseous tritium light source" (GTLS). Because tritium in particular is an integral part of thermonuclear devices (though in quantities several thousand times larger than that in a keychain), devices containing tritium are considered dual-use technology in the U.S.A., and are therefore illegal for export. However, they are widely available in the U.K., most of Europe (some countries like Belgium have outlawed them however), Asia and Australia. Tritium devices can be purchased in the UK and Australia, but are illegal for import to the United States, however they are available in the US as gunsights and for military applications. UK Source AU Source USA Source (Military Personnel only) You can also find tritium lighting in the US without having to be military personnel at They have a limited stock, though.

Mechanical Engineering
Visible Light Spectrum

Can visible light travel faster in a vacuum than both xrays and radio waves?


We call it the "speed of light", but it's also the speed of radio, X-rays, heat,

ultraviolet, microwave, gamma rays, etc, and all forms of electromagnetic radiation travel at the same speed, as long as they're in the same medium (vacuum or material substance).

Visible Light Spectrum

Where do visible light waves come from?

There are a great many sources of visible light.

They include:

-- stars

-- fire

-- volcanos

-- lightning

-- incandescent lamp filaments

-- electric sparks/arcs

-- fireflies

-- excited/ionized gas

-- flashlights

-- stove burners

Visible Light Spectrum

A painted wall appears yellow because?

The paint absorbs blue light, which means red and green light are preferentially reflected and red and green combined appear yellow.

This may be the reverse of what you learned in art class; the reason is that mixing pigmentsinvolves subtractiveprimary colors and mixing light involves additivecolors. Shine a red and a green light on the same spot and it will appear yellow.

Electromagnetic Radiation
Visible Light Spectrum

What is the difference between Free Electron Theory and Band Theory of solids?

Free Electron Theory:

This theory tells that, metals conduct electricity because of the presence of free electrons in it. The outermost shells of metal atoms will be loosely bound with their nucleus. So the electrons in it are free to move anywhere in the solid.These electrons are called free electrons and they are responsible for the conduction of electricity.

Band theory of solids:

A solid is assumed to contain many bands in which the electrons in it are packed. The most important are valence band and conduction band. The energy of electrons in these bands will be different.The difference in energies of valence band and conduction band determines whether the solid is a conductor, semi - conductor or insulator.For insulators, the difference between energies of them ( energy gap ) will be very high, and for conductor, these bands overlap each other.

The conduction band carries the electrons that conduct electricity, but the valence band has all the electrons in the ground state. Whether they go into the conduction band depends on the temperature and the energy gap between the bands. In a conductor, these bands overlap, and hence many electrons can become conducting. Thus, Band Theory explains distinction between metals and insulators, which Free Electron theory cannot do (since it assumes all valence electrons become conducting). Calculations are be performed to see which materials will have big energy gaps and which will have overlapping bands.

Headlights Tail and Brake Lights
Chevy Silverado
Visible Light Spectrum

Why do you use tail lights?

Tail lights in automobiles are in use for the simple reason that cars behind you can see you at a glance. A car without tail lights can easily be camouflaged, in the right environment. Tail lights ensure that this does not happen, especially when a car is braking. and so me nor any of my brothers in arms dont pull you over that is always a easy way to meet quota

Visible Light Spectrum

How does light travel through a camera?

The Lens is the image-forming device on a camera. The lens bends light rays to project an image onto a light sensitive medium, which may be any of several forms, including film, sensitized glass plate, or electronic sensor.

The Diaphragm is a variable opening which controls the quantity (brightness) of light falling on the light sensitive medium.

The Shutter controls the length of time light is permitted to fall on the light sensitive medium. It can take many forms, but usually has some method for precision adjustment of the time it is open.

Light passing through the lens, aperture, and (when open) the shutter forms an image of specific brightness for a specific duration on the light sensitive medium.

Light also passes through a viewfinder system, which may be a part of the optical system of the camera, or separate from it. In the most complex cameras, some of the light passing through the lens is diverted into a viewfinder by means of a mirror or prism. By using some of the same light passing into the camera, these systems permit the user to see essentially what the camera is seeing.

(See discussion)

Visible Light Spectrum

Which color has the longest wavelength?

Of the colors in the visible spectrum, red has the lowest frequency and the longest wavelength. As you move on "up" the spectrum, wavelengths get shorter.

Red has the longest spectrum of all visible light. But infrared is even longer and there are many more "colors" but you can't see them.

Visible Light Spectrum

Is there a visible light absorbing spray paint?

Yes. It is marketed under the generic product description "flat black".

Note: You may from time to time encounter an advertisement promoting "fat back",

particularly in close proximity to ethnic restaurants. Do not be misled, for that is an

entirely different product.

Acids and Bases
Visible Light Spectrum

How does light effect the pH of different liquids?

It doesn't

Electromagnetic Radiation
Visible Light Spectrum

How much energy does Uv Light Visible Light and X-Rays have?

X-ray energies in the range 120 eV to 120 keV. UV energies from 3eV to 124 eV.

Visible Light Spectrum

What Type of light comes from a black light?

A true "black light" should emit only ultraviolet radiation.

Violet light waves have the highest frequency visible to a human eye. Ultraviolet has a higher frequency, and the human eye cannot detect it.

When you buy a "black light" at the party store, in addition to the ultraviolet radiation, the bulb will usually give off violet light as well (analogous to a yellow light bulb looking a bit orange).

You can see the violet light, but it's really the invisible, high energy ultraviolet light that provides all the "cool" effects.

Visible Light Spectrum

Why is visible lights good?

They aid in helping you to see things.

Visible Light Spectrum

Why does cytochrome c absorb uv and visible light?

It contains amino acids with aromatic groups


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