Light or “visible light” refers to the visible region of the electromagnetic spectrum – that is, the range of wavelengths that trigger brightness and colour perception in humans.

For example, the sun produces visible light. Incandescent light bulbs, fluorescent, and neon lights are other examples of visible light that we may see on a regular basis. Visible light is probably the most important of all electromagnetic waves for most of us.

Light intensity refers to the strength or amount of light produced by a specific lamp source. It is the measure of the wavelength-weighted power emitted by a light source.

Visible light is one way energy moves around. Light waves are the result of vibrations of electric and magnetic fields, and are thus a form of electromagnetic (EM) radiation. Our eyes perceive different wavelengths of light as the rainbow hues of colors. Red light has relatively long waves, around 700 nm long.

We often use visible light images to see clouds and to help predict the weather. We not only look at the Earth from space but we can also look at other planets from space.

The reason that the human eye can see the spectrum is because those specific wavelengths stimulate the retina in the human eye. The light reflected from an object and which we recognize as color is (with the exception of man-made monochromatic light) a mixture of light at various wavelengths within the visible region.

The human eye can only see visible light, but light comes in many other “colors”—radio, infrared, ultraviolet, X-ray, and gamma-ray—that are invisible to the naked eye. On one end of the spectrum there is infrared light, which, while too red for humans to see, is all around us and even emitted from our bodies.

Ultimately, if you could see all wavelengths simultaneously, there would be so much light bouncing about that you wouldn’t see anything. Or rather, you would see everything and nothing simultaneously. The excess of light would just leave everything in a senseless glow.

Raging debate is finally extinguished thanks to study that puts distance at just 1.6 miles. The human eye can distinguish up to 10 million different colours and switch focus in a fraction of a second.

Red-green and yellow-blue are the so-called “forbidden colors.” Composed of pairs of hues whose light frequencies automatically cancel each other out in the human eye, they’re supposed to be impossible to see simultaneously. The limitation results from the way we perceive color in the first place.

Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to about 750 nanometers. In terms of frequency, this corresponds to a band in the vicinity of 400–790 THz.

aThe human eye can see light with wavelengths between 380 and 700 nanometers. cMost humans cannot see ultraviolet light because it has a shorter wavelength than violet light, putting it outside of the visible spectrum.

The human eye and brain together translate light into color. Light receptors within the eye transmit messages to the brain, which produces the familiar sensations of color. Rather, the surface of an object reflects some colors and absorbs all the others. We perceive only the reflected colors.

Blue

Explanation: Here are the true colors of planet Earth. Blue oceans dominate our world, while areas of green forest, brown mountains, tan desert, and white ice are also prominent. Oceans appear blue not only because water itself is blue but also because seawater frequently scatters light from a blue sky.

These color pigments come from the diet of animals and are responsible for the color of their skins, eyes, organs. But this was not the case with a blue color. Scientists confirm that blue, as we see in plants and animals, is not pigment at all.

Although it often occurs on the basal blotch of tulips, it never completely tints the blooms, and even if there are tulip varieties called blue, like for example Blue Diamond or Blue Wow, their blooms are actually violet or lilac and never really reach a genuinely blue colour.

If we’re talking proportions, the majority of your blood—55 per cent to be exact—is actually kind of yellow. That’s because, while red blood cells give blood its rosy colour, they’re only one part of the picture. In fact, blood is made up of four components: red blood cells, white blood cells, platelets and plasma.

Blood in the human body is red regardless of how oxygen-rich it is, but the shade of red may vary. The level or amount of oxygen in the blood determines the hue of red. As blood leaves the heart and is oxygen-rich, it is bright red. When the blood returns to the heart, it has less oxygen.

The colors of arterial and venous blood are different. Oxygenated (arterial) blood is bright red, while dexoygenated (venous) blood is dark reddish-purple. The dark blood in veins absorbs this red light so we see predominantly reflected blue light from the skin surface.

Flatworms, nematodes, and cnidarians (jellyfish, sea anemones, and corals) do not have a circulatory system and thus do not have blood. Their body cavity has no lining or fluid within it. They obtain nutrients and oxygen directly from the water that they live in.

Brachiopods

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