Light - is one of several kinds of radiation. Its source can be the sun, incandescent lamps or other body. Light penetrates through the transparent water, air or glass. From most of the others, especially is reflected through brilliant as a mirror material. Through light we can see and communicate with each other. The sun and the burning lamps, TV screen or just open fire glow with its own light. A majority of the objects surrounding us, do not emit light, and we see them only because they reflect light and it enters our eyes. Objects of white colors reflect more light and therefore appear brighter. Black is almost completely absorbs the light and does not reflect it at all. From mirror, light reflected completely without loss and distortion, so looking at it, our eyes, see it as our reflection. Generally the propagation of light is on the right lines, but if on its way there a barrier through which it passes, then formed its shadow . When light enters the transparent medium, such as water or glass by 90 degrees then reverses its direction. This phenomenon is called refraction. This is due to less than the air velocity of light therein. That is why a straw in a glass with a transparent drink looks bruised.
Colors and waves
White light is a mixture of all colors of the spectrum. Spectrum - all components of light that can be seen by passing white light through a prism (four-sided triangular glass bar). All components of the colors are refracted in a prism at different angles, and a set of colors (spectrum) becomes visible. Light is a collection of over short waves radiating from a source like waves of water on its surface diverging from the thrown stone. The distance from the top of one wave to another is called a wavelength. In light, these distances are negligible: more than 2,000 waves fit on the head of a pin. Light of different colors and has a different wavelength. The longest wavelength has red light. And soon - purple. The visible light to our eyes, only one of the numerous family of electromagnetic waves. Yet, it includes an infrared and ultraviolet radiation, X-rays and radio waves, they permeate space at the same speed close to 300 thousand. Km / s. In all the universe there is nothing moves faster. At this rate, one second can go around the Earth more than seven times.
Lighting and lamps
The substance begins to emit light if it is heated to a temperature higher than 700 degrees C. The sun, lamps and light sources are light because they are very hot. The incandescent lamp current passing through the tungsten filament, it heats white hot. Using electricity, light obtained by other methods. Lamps street lamps filled with sodium vapor, which by passing electric current through them lit yellow. A glass tube filled with neon, will give red light. And fluorescent lamps lit mercury vapor, when current passes through them, and they emit ultraviolet rays invisible to the eye. Special composition applied to the inside wall of the tube, it absorbs light itself. Fluorescent dyes glow, thanks to always present in sunlight, ultraviolet radiation.
Light signals
Since ancient times, people have learned to communicate across large distances on land and water by means of flashes of signal lanterns. In our time, the flash of laser light passing through fiber optic cable to carry thousands of kilometers phone conversations, video images and computer data. Fiber optic cables are made up of glass fibers (fibers) which are not thicker than a hair. A laser beam entering therein can not go anywhere except on the other end of the filament. The laser is controlled by a special electronic system emits pulses millions of times per second. Flash Laser - digital codes obtained transfer numbers. At the other end of the fiber, these newly converted to flash video image or sound can be found.
From the history of the world
People use various lamps from time immemorial. The first candle appeared about 2 million years ago in Egypt. In the early 19th century, widespread gas street lights, but their light flickered and was not bright. The invention of gas grid allowed us to solve these problems. It was a cover of the matter, impregnated chemical composition of glowing bright white light when heated. The first incandescent glow from electricity appeared thanks to the efforts of Joseph Swan and Thomas Edison in the late 70s of the 19th century. These lamps became the ancestors of today's incandescent bulbs. Now they are not expensive, but still emit more heat rather than light. More effective small fluorescent tubes that consume energy in less than five times the emission of the same amount of light. The use of these light sources not only helps to save money on electricity, but also to conserve natural resources (coal, gas, oil) burnt in thermal power stations. And improve the environmental situation of the country. After all, with less energy consumption, will burn less fuel and emissions will also become smaller. So the air in cities and villages will be cleaner, and people living in them will be healthier.
White light is a mixture of all colors of the spectrum. Spectrum - all components of light that can be seen by passing white light through a prism (four-sided triangular glass bar). All components of the colors are refracted in a prism at different angles, and a set of colors (spectrum) becomes visible. Light is a collection of over short waves radiating from a source like waves of water on its surface diverging from the thrown stone. The distance from the top of one wave to another is called a wavelength. In light, these distances are negligible: more than 2,000 waves fit on the head of a pin. Light of different colors and has a different wavelength. The longest wavelength has red light. And soon - purple. The visible light to our eyes, only one of the numerous family of electromagnetic waves. Yet, it includes an infrared and ultraviolet radiation, X-rays and radio waves, they permeate space at the same speed close to 300 thousand. Km / s. In all the universe there is nothing moves faster. At this rate, one second can go around the Earth more than seven times.
Lighting and lamps
The substance begins to emit light if it is heated to a temperature higher than 700 degrees C. The sun, lamps and light sources are light because they are very hot. The incandescent lamp current passing through the tungsten filament, it heats white hot. Using electricity, light obtained by other methods. Lamps street lamps filled with sodium vapor, which by passing electric current through them lit yellow. A glass tube filled with neon, will give red light. And fluorescent lamps lit mercury vapor, when current passes through them, and they emit ultraviolet rays invisible to the eye. Special composition applied to the inside wall of the tube, it absorbs light itself. Fluorescent dyes glow, thanks to always present in sunlight, ultraviolet radiation.
Light signals
Since ancient times, people have learned to communicate across large distances on land and water by means of flashes of signal lanterns. In our time, the flash of laser light passing through fiber optic cable to carry thousands of kilometers phone conversations, video images and computer data. Fiber optic cables are made up of glass fibers (fibers) which are not thicker than a hair. A laser beam entering therein can not go anywhere except on the other end of the filament. The laser is controlled by a special electronic system emits pulses millions of times per second. Flash Laser - digital codes obtained transfer numbers. At the other end of the fiber, these newly converted to flash video image or sound can be found.
From the history of the world
People use various lamps from time immemorial. The first candle appeared about 2 million years ago in Egypt. In the early 19th century, widespread gas street lights, but their light flickered and was not bright. The invention of gas grid allowed us to solve these problems. It was a cover of the matter, impregnated chemical composition of glowing bright white light when heated. The first incandescent glow from electricity appeared thanks to the efforts of Joseph Swan and Thomas Edison in the late 70s of the 19th century. These lamps became the ancestors of today's incandescent bulbs. Now they are not expensive, but still emit more heat rather than light. More effective small fluorescent tubes that consume energy in less than five times the emission of the same amount of light. The use of these light sources not only helps to save money on electricity, but also to conserve natural resources (coal, gas, oil) burnt in thermal power stations. And improve the environmental situation of the country. After all, with less energy consumption, will burn less fuel and emissions will also become smaller. So the air in cities and villages will be cleaner, and people living in them will be healthier.
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