what is electromagnetic spectrum?
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The electromagnetic spectrum is the range of all possible electromagnetic radiation. Also, the "electromagnetic spectrum" (usually just spectrum) of an object is the range of electromagnetic radiation that it emits, reflects, or transmits.\n\nThe electromagnetic spectrum, shown in the table, extends from frequencies used in the electric power grid (at the long-wavelength end) to gamma radiation (at the short-wavelength end), covering wavelengths from thousands of kilometres down to fractions of the size of an atom. It is commonly said that EM waves beyond these limits are uncommon, although this is not actually true. The 22-year sunspot cycle, for instance, produces radiation with a period of 22 years, or a frequency of 1.4*10-9 Hz. At the other extreme, photons of arbitrarily high frequency may be produced by colliding electrons with positrons at appropriate energy. 1024 Hz photons can be produced today with man-made accelerators. In our universe the short wavelength limit is likely to be the Planck length, and the long wavelength limit the size of the universe itself (see cosmology), though in principle the spectrum is infinite.
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From Wikipedia: "The visible spectrum (or sometimes optical spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. There are no exact bounds to the visible spectrum; a typical human eye will respond to wavelengths from 400 to 700 nm, although some people may be able to perceive wavelengths from 380 to 780 nm."
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ELECTROMAGNETIC ENERGY is ENERGY coming from the POLARIZEd motion of ELECTRONs, but i don't think LIGHT is ELECTROMAGNETic ENERGY. For me, LIGHT is a FORM of QUANTUM ENERGY.
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Light waves are in the visual spectrum and so they bounce off of solid objects.. Radio waves like X rays are in a non visual spectrum and penetrate.
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Electromagnetic radiation travels (propagates) by means of oscillating electromagnetic fields that pass through the air and the vacuum of space equally well, and does not require a medium of transport (such as the aether). When radio waves pass an electrical conductor, the oscillating electric or magnetic field (depending on the shape of the conductor) induces an alternating current and voltage in the conductor. This can be transformed into audio or other signals that carry information. The word 'radio' is used to describe this phenomenon, and television, radio, radar, and cell phone transmissions are all classed as radio frequency emissions.
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The visible spectrum (or sometimes optical spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light.\n\nCheck the attached link for visible response.
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The electromagnetic waves used by cell phones are called radio waves. Waves are characterized by their frequency; that is, the number of times that the wave pattern repeats in a second (or some other time interval). For example, the radio waves that a type of cell phone called a GSM phone use are in frequency bands centered on 850 MHz, 900 MHz, 1800 MHZ and 1900 MHz. That is, the radio waves that a GSM cell phone using the 850 MHz band oscillate roughly 850 million times every second (the pattern repeats 850 million times every second). \n\nThe radio waves that travel back and forth from the cell phone tower to your cell phone are electromagnetic. Your voice signal on the cell phone is carried by modulating electromagnetic waves. No electromagnetic waves, no signal, and therefore, no cell phone.  Without electromagnetic waves, there would be no radio, no tv and no cell phones, and no cordless phones, and no wireless PCs etc etc.\n\nAll light is electromagnetic waves. All heat is electromagnetic waves. Electricity is actually an electromagnetic wave travelling in a wire (the electrons move much slower than this wave). So without electromagnetic waves, the universe would be a very different place.
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A spectrum is the derivative of broken light through a triangular shaped crystal, giving  as a result a spectrum or a rainbow of colors, and is used to determine many things about the light source. e.i. the composition of elements or gases of the source, among other uses. How scientists determine results is by measuring the amplitude and intensity of each color in the spectrum.
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A material's emission spectrum is the amount of electromagnetic radiation of each frequency it emits when it is heated (or more generally when it is excited).\n\nWhen the electrons in the element are excited, they jump to higher energy levels. As the electrons fall back down, and leave the excited state, energy is re-emitted, the wavelength of which refers to the discrete lines of the emission spectrum. Note however that the emission extends over a range of frequencies, an effect called spectral line broadening.\n\nThe term often refers to the visible light emission spectrum, although it extends to the whole electromagnetic spectrum, from the low energy radio waves up to high energy gamma rays.\n\nThe emission spectrum can be used to determine the composition of a material, since it is different for each element of the periodic table. One example is identifying the composition of stars by analysing the received light.
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wireless application protocols (WAP), 3g, gprs etc... mostly using gigahertz frequencies under environmental health spectrum, around 3.5GHz.... these spectrum also covers radio waves and microwaves, some transmitted via satelites.
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They are alll electromagnetic waves.  They all have different frequencies.  Radio waves have the lowest and gamma rays have the highest.
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Refer to an electromagnetic spectrum. \nRadiation is emission and propagation and emission of energy in the form of rays or waves (http://dictionary.reference.com/search?q=radiation).\nIn other words as long as waves travel there is radiation.\nThere are two types of radiation, the ionizing (harmful) radiation and the non-ionizing (not harmful) radiation.\nYou can see it in a magnetic spectrum. High frequency and low wavelength are those ionizing radiation. High wavelenth and low frequency are those non-ionizing radiation. Penetration of these waves are dependent on their frequencies. High frequencies are able to tranmsmit objects. \nFrom the magnetic spectrum there are different kinds of waves, (from ionizing to non-ionizing) radiowaves, microwaves, infrared, white light, UV, x-rays, gamma rays cosmic rays. These waves travel in a straight line unless scattered by hitting an object or being blocked or interrupted or you know I mean.\nThat's why astronomers detect radiowaves from the outerspace.\nSo if you asked, how does radiant energy reach earth, is simply because they travelled a striaght line from their source.
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Energy increases with increasing frequency (radio waves=low freq, gamma rays=high freq).  All electromagnetic rays are invisible, except for the ones that are in the range of visible frequencies (duh?).  And "light" is simply another name for electromagnetic waves.
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Light energy is a form of electromagnetic radiation and is found in a segment of the (EM) electromagnetic spectrum. \n\nThe EM spectrum encompasses the entire range of ionizing and non-ionizing radiation extending in frequency from approximately 1023 hertz to 0 hertz, or in corresponding wavelengths, from 10-13 centimeter to infinity. \n\nThis spectrum includes all forms of classical non-ionizing radiation we are familiar with including ultraviolet light, VISIBLE LIGHT, infrared (light) radiation, microwaves, and radio waves. The spectrum also includes ionizing radiation such as cosmic-ray photons, gamma rays, x-rays. \n\nAt eithe end of the visible light spectrum is infared and ultraviolet light and humans cannot perceive these spectrums of light.  Red colored light is longer wavelength of light and visible violet light is shorter wavelength.\n\nFor a cool chart and more in depth descriptin of the EM spectrum check out the Goddard Space Center's special page on this topic. \n\nhttp://imagine.gsfc.nasa.gov/docs/science/science.html   Use the link that says The Electromagetic Spectrum
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Light and radio signals are all the same thing, electromagnetic radiation. Radio waves are just very low frequency light and light is just very high frequency radio signals. All objects that are hotter than absolute zero give off some electromagnetic radiation. The really hot objects give off visible light. Cooler ones give off infra red light. Cooler still and you get radio emissions. The Earth's surface gives off radio waves because it is warm. In fact, it gives off so much that it is an interference for communication satellites trying to hear signals from the ground.\n\nModern radio astronomy uses giant antennas to focus radio waves, just like optical telescopes focus visible light. Computers are used to construct images of what the sky would look like if your eyes could see radio waves.
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Synchrotron radiation is electromagnetic radiation, similar to cyclotron radiation, but generated by the acceleration of ultrarelativistic (i.e., moving near the speed of light) electrons through magnetic fields. This may be achieved artificially by storage rings in a synchrotron, or naturally by fast moving electrons moving through magnetic fields in space. The radiation typically includes infrared, optical, ultraviolet, x-rays.
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heat is not electromagnetic radiation, it's molecular kinetic energy (or thermal energy).  The sun emits Ultraviolet radiation, amongst other emissions in the light spectra, but i don't believe the heat emitted can be attributed to an electromagnetic wave.