The Electromagnetic Waves And Spectrum

The Electromagnetic Waves And Spectrum The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The electromagnetic spectrum of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. The electromagnetic spectrum is a continuum of all electromagnetic waves arranged according to frequency and wavelength. The electromagnetic spectrum extends from low frequencies used for modern radio to gamma radiation at the short-wavelength end, covering wavelengths from thousands of kilometres down to a fraction of the size of an atom. The long wavelength limit is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length, although in principle the spectrum is infinite and continuous. The sun, earth, and other bodies radiate electromagnetic energy of varying wavelengths. Electromagnetic energy passes through space at the speed of light in the form of sinusoidal waves. The wavelength is the distance from wave crest to wave crest (see figure below). Light is a particular type of electromagnetic radiation that can be seen and sensed by the human eye, but this energy exists at a wide range of wavelengths. The micron is the basic unit for measuring the wavelength of electromagnetic waves. The spectrum of waves is divided into sections based on wavelength. The shortest waves are gamma rays, which have wavelengths of 10e-6 microns or less. The longest waves are radio waves, which have wavelengths of many kilometres. The range of visible consists of the narrow portion of the spectrum, from 0.4 microns (blue) to 0.7 microns (red). RANGE OF THE SPECTRUM EM waves are typically described by any of the following three physical properties: the frequency f, wavelength ÃŽÂ », or photon energy E. Frequencies range from 2.4ÃÆ'-1023 Hz (1 GeV gamma rays) down to the local plasma frequency of the ionized interstellar medium (~1kHz). Wavelength is inversely proportional to the wave frequency, so gamma rays have very short wavelengths that are fractions of the size of atoms, whereas wavelengths can be as long as the universe. Photon energy is directly proportional to the wave frequency, so gamma rays have the highest energy (around a billion electron volts) and radio waves have very low energy (around femto electron volts). These relations are illustrated by the following equations: Where: c = 299,792,458 m/s is the speed of light in vacuum and h = 6.62606896(33) ÃÆ'-10à ¢Ã‹â€ Ã¢â‚¬â„¢34 J s = 4.13566733(10) ÃÆ'-10à ¢Ã‹â€ Ã¢â‚¬â„¢15 eV s is Plancks constant. Whenever electromagnetic waves exist in a medium with matter, their wavelength is decreased. Wavelengths of electromagnetic radiation, no matter what medium they are travelling through, are usually quoted in terms of the vacuum wavelength, although this is not always explicitly stated. Generally, EM radiation is classified by wavelength into radio wave, microwave, infrared, the visible region we perceive as light, ultraviolet, X-rays and gamma rays. The behaviour of EM radiation depends on its wavelength. When EM radiation interacts with single atoms and molecules, its behaviour also depends on the amount of energy per quantum (photon) it carries. Spectroscopy can detect a much wider region of the EM spectrum than the visible range of 400 nm to 700 nm. A common laboratory spectroscope can detect wavelengths from 2 nm to 2500 nm. Detailed information about the physical properties of objects, gases, or even stars can be obtained from this type of device. Spectroscopes are widely used in astrophysics. For example, many hydrogen atoms emit a radio wave photon which has a wavelength of 21.12 cm. Also, frequencies of 30 Hz and below can be produced by and are important in the study of certain stellar nebulae and frequencies as high as 2.9ÃÆ'-1027 Hz have been detected from astrophysical sources. - The Spectrum of Electromagnetic Waves While the classification scheme is generally accurate, in reality there is often some overlap between neighbouring types of electromagnetic energy. For example, SLF radio waves at 60 Hz may be received and studied by astronomers, or may be ducted along wires as electric power, although the latter is, strictly speaking, not electromagnetic radiation at all (see near and far field) The distinction between X and gamma rays is based on sources: gamma rays are the photons generated from nuclear decay or other nuclear and sub nuclear/particle process, whereas X-rays are generated by electronic transitions involving highly energetic inner atomic electrons. Generally, nuclear transitions are much more energetic than electronic transitions, so usually, gamma-rays are more energetic than X-rays, but exceptions exist. By analogy to electronic transitions, muonic atom transitions are also said to produce X-rays, even though their energy may exceed 6 mega electron volts (0.96 pJ), whereas there a re many (77 known to be less than 10 keV (1.6 fJ)) low-energy nuclear transitions (e.g. the 7.6 eV (1.22 aJ) nuclear transition of thorium-229), and despite being one million-fold less energetic than some muonic X-rays, the emitted photons are still called gamma rays due to their nuclear origin. Also, the region of the spectrum of the particular electromagnetic radiation is reference-frame dependent (on account of the Doppler shift for light) so EM radiation which one observer would say is in one region of the spectrum could appear to an observer moving at a substantial fraction of the speed of light with respect to the first to be in another part of the spectrum. For example, consider the cosmic microwave background. It was produced, when matter and radiation decoupled, by the de-excitation of hydrogen atoms to the ground state. These photons were from Lyman series transitions, putting them in the ultraviolet (UV) part of the electromagnetic spectrum. Now this radiation has undergone enough cosmological red shift to put it into the microwave region of the spectrum for observers moving slowly (compared to the speed of light) with respect to the cosmos. However, for particles moving near the speed of light, this radiation will be blue-shifted in their rest frame. The highest energy cosmic ray protons are moving such that, in their rest frame, this radiation is blueshifted to high energy gamma rays which interact with the proton to produce bound quark-antiquark pairs (pions). This is the source of the GZK limit Radio Waves: whose wavelength range from more than 104 m to about 0.1m, are the results of charges accelerating through conducting wires. They are generated by such electronic devices as LC oscillators and are used in radio and television communication systems. Radio waves generally are utilized by antennas of appropriate size (according to the principle of resonance), with wavelengths ranging from hundreds of meters to about one millimetre. They are used for transmission of data, via modulation. Television, mobile phones, wireless networking and amateur radio all use radio waves. The use of the radio spectrum is regulated by many governments through frequency allocation. Radio waves can be made to carry information by varying a combination of the amplitude, frequency and phase of the wave within a frequency band. When EM radiation impinges upon a conductor, it couples to the conductor, travels along it, and induces an electric current on the surface of that conductor by exciting the electrons of the conducting material. This effect (the skin effect) is used in antennas. EM radiation may also cause certain molecules to absorb energy and thus to heat up, causing thermal effects and sometimes burns. This is exploited in microwave ovens. Microwaves: The super high frequency (SHF) and extremely high frequency (EHF) of microwaves come next up the frequency scale. Microwaves are waves which are typically short enough to employ tubular metal waveguides of reasonable diameter. They have wavelengths ranging from approximately 0.3m to 10-4 m and are also generated by electronic devices. Because of their short wave lengths, they are well suited for radar system and for studying atomic and molecular properties of matter. Microwave ovens are an interesting domestic application of these waves. It has been suggested that the solar energy could be harnessed by beaming microwaves to the earth from a solar collector in space. Microwave energy is produced with klystron and magnetron tubes, and with solid state diodes such as Gunn and IMPATT devices. Microwaves are absorbed by molecules that have a dipole moment in liquids. In a microwave oven, this effect is used to heat food. Low-intensity microwave radiation is used in Wi-Fi, although this is at intensity levels unable to cause thermal heating. Volumetric heating, as used by microwaves, transfer energy through the material electromagnetically, not as a thermal heat flux. The benefit of this is a more uniform heating and reduced heating time; microwaves can heat material in less than 1% of the time of conventional heating methods. When active, the average microwave oven is powerful enough to cause interference at close range with poorly shielded electromagnetic fields such as those found in mobile medical devices and cheap consumer electronics. Infrared Waves: have wavelengths ranging from approximately 10-3m to the longest wavelength of visible light, 710-7m. These waves, produced by molecules and room temperature objects, are readily absorbed by most materials. The infrared energy absorbed by a substance appears as internal energy because the energy agitates objects atoms, increasing their vibrational or translational motion, which results in a temperature increase. Infrared radiation has practical and scientific applications in many areas, including physical therapy, IR photography and vibrational spectroscopy. The infrared part of the electromagnetic spectrum covers the range from roughly 300 GHz (1 mm) to 400 THz (750 nm). It can be divided into three parts: Far-infrared, from 300 GHz (1 mm) to 30 THz (10 ÃŽÂ ¼m). The lower part of this range may also be called microwaves. This radiation is typically absorbed by so-called rotational modes in gas-phase molecules, by molecular motions in liquids, and by phonons in solids. The water in the Earths atmosphere absorbs so strongly in this range that it renders the atmosphere effectively opaque. However, there are certain wavelength ranges (windows) within the opaque range which allow partial transmission, and can be used for astronomy. The wavelength range from approximately 200 ÃŽÂ ¼m up to a few mm is often referred to as sub-millimetre in astronomy, reserving far infrared for wavelengths below 200 ÃŽÂ ¼m. Mid-infrared, from 30 to 120 THz (10 to 2.5 ÃŽÂ ¼m). Hot objects (black-body radiators) can radiate strongly in this range. It is absorbed by molecular vibrations, where the different atoms in a molecule vibrate around their equilibrium positions. This range is sometimes called the fingerprint region since the mid-infrared absorption spectrum of a compound is very specific for that compound. Near-infrared, from 120 to 400 THz (2,500 to 750 nm). Physical processes that are relevant for this range are similar to those for visible light. Visible light: It is the most familiar form of electromagnetic spectrum the human eye can detect. Light is produced by the rearrangement of electrons in atoms and molecules. The various wavelengths of visible light, which correspond to different colours, range from red (ÃŽÂ »=710-7) to violet (ÃŽÂ »=410-7). The sensitivity of the human eye is a function of wavelength, being a maximum of 5.510-7m. This is the range in which the sun and stars similar to it emit most of their radiation. It is probably not a coincidence that the human eye is sensitive to the wavelengths that the sun emits most strongly. Visible light (and near-infrared light) is typically absorbed and emitted by electrons in molecules and atoms that move from one energy level to another. The light we see with our eyes is really a very small portion of the electromagnetic spectrum. A rainbow shows the optical (visible) part of the electromagnetic spectrum; infrared (if you could see it) would be located just beyond the red side of the rainbow with ultraviolet appearing just beyond the violet end. Electromagnetic radiation with a wavelength between 380 nm and 760 nm (790-400 terahertz) is detected by the human eye and perceived as visible light. Other wavelengths, especially near infrared (longer than 760 nm) and ultraviolet (shorter than 380 nm) are also sometimes referred to as light, especially when the visibility to humans is not relevant. If radiation having a frequency in the visible region of the EM spectrum reflects off an object, say, a bowl of fruit, and then strikes our eyes, this results in our visual perception of the scene. Our brains visual system processes the multitude of reflected frequencies into different shades and hues, and through this not-entirely-understood psychophysical phenomenon, most people perceive a bowl of fruit. At most wavelengths, however, the information carried by electromagnetic radiation is not directly detected by human senses. Natural sources produce EM radiation across the spectrum, and our technology can also manipulate a broad range of wavelengths. Optical fiber transmits light which, although not suitable for direct viewing, can carry data that can be translated into sound or an image. The coding used in such data is similar to that used with radio waves. Ultraviolet light: These cover wavelengths ranging from approximately 410-7 to 610-10m. The sun is an important source of ultraviolet (UV) light, which is the main cause of sun burn. Sunscreen lotions are transparent to visible light but absorb most of the ultraviolet light. The higher a sunscreens solar protection factor, or SPF, the greater the percentage of UV light absorbed. Ultraviolet rays have also been implicated in the formation of cataracts, a clouding of lens inside the eye. Most of the UV light from the sun is absorbed by ozone (O3) molecules in the earths upper atmosphere, in a layer called the stratosphere. This ozone shield converts lethal high energy UV energy into IR radiation, which in turn warms the stratosphere. Next in frequency comes ultraviolet (UV). This is radiation whose wavelength is shorter than the violet end of the visible spectrum, and longer than that of an X-ray. Being very energetic, UV can break chemical bonds, making molecules unusually reactive or ionizing them (see photoelectric effect), in general changing their mutual behaviour. Sunburn, for example, is caused by the disruptive effects of UV radiation on skin cells, which is the main cause of skin cancer, if the radiation irreparably damages the complex DNA molecules in the cells (UV radiation is a proven mutagen). The Sun emits a large amount of UV radiation, which could quickly turn Earth into a barren desert. However, most of it is absorbed by the atmospheres ozone layer before reaching the surface. X-rays: They have wavelengths in the range from approximately 10-8m to 10-12m. The most common source of x-rays is the stopping of high-energy electrons upon bombarding a metal target. X-rays are used as a diagnostic tool in medicine (a process known as radiography) and as a treatment for certain forms of cancer as well as for high-energy physics and astronomy.. Because x-rays can damage or destroy living tissues and organisms, care must be taken to avoid unnecessary exposure or over exposure. X-rays are also used in the study of crystal structure because x-ray wavelengths are comparable to the atomic separation distances in solids (about 0.1nm). Hard X-rays have shorter wavelengths than soft X-rays., Neutron stars and accretion disks around black holes emit X-rays, which enable us to study them. X-rays are given off by stars and are strongly emitted by some types of nebulae. Gamma rays: After hard X-rays comes gamma rays, which were discovered by Paul Villard in 1900, these are the most energetic photons, having no defined lower limit to their wavelength. They are electromagnetic waves emitted by radioactive nuclei (such as 60Co and 137Cs) and during certain nuclear reactions. High-energy gamma rays are a component of cosmic rays that enter the earths atmosphere from space. They have wavelength ranging from approximately 10-10m to less than 10-14m. Gamma rays are highly penetrating and produce serious damage when absorbed by living tissues. Consequently those working near such dangerous radiation must be protected with heavily absorbing material such as thick layers of lead. They are useful to astronomers in the study of high energy objects or regions, and find a use with physicists thanks to their penetrative ability and their production from radioisotopes. Gamma rays are also used for the irradiation of food and seed for sterilization, and in medicine they are used in radiation cancer therapy and some kinds of diagnostic imaging such as PET scans. The wavelength of gamma rays can be measured with high accuracy by means of Compton scattering. Note: There are no precisely defined boundaries between the bands of the electromagnetic spectrum. Radiations of some types have a mixture of the properties of those in two regions of the spectrum. For example, red light resembles infrared radiation in that it can resonate some chemical bonds. Application Areas of Electromagnetic Waves Electromagnetic Waves in the modern world have led to evolvement of many advanced communication systems some of them are radio, television, radars, etc. We would now focus on how these electromagnetic waves which carry energy and momentum are used in various applications round the globe. TELEMETRY Telemetry is the process of making measurements from a remote location and transmitting those measurements to receiving equipment. The earliest telemetry systems, developed in the United States during the 1880s, monitored the distribution and use of electricity in a given region, and relayed this information back to power companies using telephone lines. By the end of World War I, electric companies used the power lines themselves as information relays, and though such electrical telemetry systems remain in use in some sectors, most modern telemetry systems apply radio signals. An example of a modern telemetry application is the use of an input device called a transducer to measure information concerning an astronauts vital signs (heartbeat, blood pressure, body temperature, and so on) during a manned space flight. The transducer takes this information and converts it into an electrical impulse, which is then beamed to the space monitoring station on Earth. Because this signal carries information, it must be modulated, but there is little danger of interference with broadcast transmissions on Earth. Typically, signals from spacecraft are sent in a range above 10 10 Hz, far above the frequencies of most microwave transmissions for commercial purposes. RADAR Radio waves can be used to send communication signals, or even to cook food; they can also be used to find and measure things. One of the most obvious applications in this regard is radar, an acronym for RAdio Detection And Ranging. Radio makes it possible for pilots to see through clouds, rain, fog, and all manner of natural phenomena-not least of which is darkness. It can also identify objects, both natural and manmade, thus enabling a peacetime pilot to avoid hitting another craft or the side of a mountain. On the other hand, radar may help a pilot in wartime to detect the presence of an enemy. Nor is radar used only in the skies, or for military purposes, such as guiding missiles: on the ground, it is used to detect the speeds of objects such as automobiles on an interstate highway, as well as to track storms. In the simplest model of radar operation, the unit sends out microwaves toward the target, and the waves bounce back off the target to the unit. Though the speed of light is reduced somewhat, due to the fact that waves are travelling through air rather than through a vacuum, it is, nonetheless, possible to account for this difference. Hence, the distance to the target can be calculated using the simple formula d = vt, where d is distance, v is velocity, and t is time. Typically, a radar system includes the following: a frequency generator and a unit for controlling the timing of signals; a transmitter and, as with broadcast radio, a modulator; a duplexer, which switches back and forth between transmission and reception mode; an antenna; a receiver, which detects and amplifies the signals bounced back to the antenna; signal and data processing units; and data display units. In a monostatic unit-one in which the transmitter and receiver are in the same location-the unit has to be continually switched between sending and receiving modes. Clearly, a bistatic unit-one in which the transmitter and receiver antennas are at different locations-is generally preferable; but on an airplane, for instance, there is no choice but to use a monostatic unit. In order to determine the range to a target-whether that target be a mountain, an enemy aircraft, or a storm-the target itself must first be detected. This can be challenging, because only a small portion of the transmitted pulse comes back to the receiving antenna. At the same time, the antenna receives reflections from a number of other objects, and it can be difficult to determine which signal comes from the target. For an aircraft in a wartime situation, these problems are compounded by the use of enemy countermeasures such as radar jamming. Still another difficulty facing a military flyer is the fact that the use of radar itself-that is the transmission of microwaves-makes the aircraft detectable to opposing forces. MICROWAVE OVENS The same microwaves that transmit FM and television signals-to name only the most obviously applications of microwave for communication-can also be harnessed to cook food. The microwave oven, introduced commercially in 1955, was an outgrowth of military technology developed a decade before. During World War II, the Raytheon Manufacturing Company had experimented with a magnetron, a device for generating extremely short-wavelength radio signals as a means of improving the efficiency of military radar. While working with a magnetron, a technician named Percy Spencer was surprised to discover that a candy bar in his pocket had melted, even though he had not felt any heat. This led him to considering the possibilities of applying the magnetron to peacetime uses, and a decade later, Raytheons radar range hit the market. Those early microwave ovens had none of varied power settings to which modern users of the microwave-found today in two-thirds of all American homes-are accustomed. In the first microwaves, the only settings were on and off, because there were only two possible adjustments: either the magnetron would produce, or not produce, microwaves. Today, it is possible to use a microwave for almost anything that involves the heating of food that contains water-from defrosting a steak to popping popcorn. As noted much earlier, in the general discussion of electromagnetic radiation, there are three basic types of heat transfer: conduction, convection, and radiation. Without going into too much detail here, conduction generally involves heat transfer between molecules in a solid; convection takes place in a fluid (a gas such as air or a liquid such as water); and radiation, of course, requires no medium. A conventional oven cooks through convection, though conduction also carries heat from the outer layers of a solid (for example, a turkey) to the interior. A microwave, on the other hand, uses radiation to heat the outer layers of the food; then conduction, as with a conventional oven, does the rest. The difference is that the microwave heats only the food-or, more specifically, the water, which then transfers heat throughout the item being heated-and not the dish or plate. Thus, many materials, as long as they do not contain water, can be placed in a microwave oven without being melted or burned. Metal, though it contains no water, is unsafe because the microwaves bounce off the metal surfaces, creating a microwave buildup that can produce sparks and damage the oven. In a microwave oven, microwaves emitted by a small antenna are directed into the cooking compartment, and as they enter, they pass a set of turning metal fan blades. This is the stirrer, which disperses the microwaves uniformly over the surface of the food to be heated. As a microwave strikes a water molecule, resonance causes the molecule to align with the direction of the wave. An oscillating magnetron causes the microwaves to oscillate as well, and this, in turn, compels the water molecules to do the same. Thus, the water molecules are shifting in position several million times a second, and this vibration generates energy that heats the water. RADIO COMMUNICATION Among the most familiar parts of the electromagnetic spectrum, in modern life at least, is radio. In most schematic representations of the spectrum, radio waves are shown either at the left end or the bottom, as an indication of the fact that these are the electromagnetic waves with the lowest frequencies, the longest wavelengths, and the smallest levels of photon energy. Included in this broad sub-spectrum, with frequencies up to about 10 7 Hertz are long-wave radio, short-wave radio, and microwaves. The areas of communication affected are many: broadcast radio, television, mobile phones, radar-and even highly specific forms of technology such as baby monitors. Though the work of Maxwell and Hertz was foundational to the harnessing of radio waves for human use, the practical use of radio had its beginnings with Marconi. During the 1890s, he made the first radio transmissions, and, by the end of the century, he had succeeded in transmitting telegraph messages across the Atlantic Ocean-a feat which earned him the Nobel Prize for physics in 1909. Marconis spark transmitters could send only coded messages, and due to the broad, long-wave length signals used, only a few stations could broadcast at the same time. The development of the electron tube in the early years of the twentieth century, however, made it possible to transmit narrower signals on stable frequencies. This, in turn, enabled the development of technology for sending speech and music over the airwaves. THE DEVELOPMENT OF AM AND FM. A radio signal is simply a carrier: the process of adding information-that is, complex sounds such as those of speech or music-is called modulation. The first type of modulation developed was AM, or amplitude modulation, which Canadian-American physicist Reginald Aubrey Fessenden (1866-1932) demonstrated with the first United States radio broadcast in 1906. Amplitude modulation varies the instantaneous amplitude of the radio wave, a function of the radio stations power, as a means of transmitting information. By the end of World War I, radio had emerged as a popular mode of communication: for the first time in history, entire nations could hear the same sounds at the same time. During the 1930s, radio became increasingly important, both for entertainment and information. Families in the era of the Great Depression would gather around large cathedral radios-so named for their size and shape-to hear comedy programs, soap operas, news programs, and speeches by important public figures such as President Franklin D. Roosevelt. Throughout this era-indeed, for more than a half-century from the end of the first World War to the height of the Vietnam Conflict in the mid-1960s-AM held a dominant position in radio. This remained the case despite a number of limitations inherent in amplitude modulation: AM broadcasts flickered with popping noises from lightning, for instance, and cars with AM radios tended to lose their signal when going under a bridge. Yet, another mode of radio transmission was developed in the 1930s, thanks to American inventor and electrical engineer Edwin H. Armstrong (1890-1954). This was FM, or frequency modulation, which varied the radio signals frequency rather than its amplitude. Not only did FM offer a different type of modulation; it was on an entirely different frequency range. Whereas AM is an example of a long-wave radio transmission, FM is on the microwave sector of the electromagnetic spectrum, along with television and radar. Due to its high frequency and form of modulation, FM offered a clean sound as compared with AM. The addition of FM stereo broadcasts in the 1950s offered still further improvements; yet despite the advantages of FM, audiences were slow to change, and FM did not become popular until the mid-to late 1960s. SIGNAL PROPAGATION AM signals have much longer wavelengths, and smaller frequencies, than do FM signals, and this, in turn, affects the means by which AM signals are propagated. There are, of course, much longer radio wavelengths; hence, AM signals are described as intermediate in wavelength. These intermediate-wavelength signals reflect off highly charged layers in the ionosphere between 25 and 200 mi (40-332 km) above Earths surface. Short-wave-length signals, such as those of FM, on the other hand, follow a straight-line path. As a result, AM broadcasts extend much farther than FM, particularly at night. At a low level in the ionosphere is the D layer, created by the Sun when it is high in the sky. The D layer absorbs medium-wavelength signals during the day, and for this reason, AM signals do not travel far during daytime hours. After the Sun goes down, however, the D layer soon fades, and this makes it possible for AM signals to reflect off a much higher layer of the ionosphere known as the F layer. (This is also sometimes known as the Heaviside layer, or the Kennelly-Heaviside layer, after English physicist Oliver Heaviside and British-American electrical engineer Arthur Edwin Kennelly, who independently discovered the ionosphere in 1902.) AM signals bounce off the F layer as though it were a mirror, making it possible for a listener at night to pick up a signal from halfway across the country. The Sun has other effects on long-wave and intermediate-wave radio transmissions. Sunspots, or dark areas that appear on the Sun in cycles of about 11 years, can result in a heavier buildup of the ionosphere than normal, thus impeding radio-signal propagation. In addition, occasional bombardment of Earth by charged particles from the Sun can also disrupt transmissions. Due to the high frequencies of FM signals, these do not reflect off the ionosphere; instead, they are received as direct waves. For this reason, an FM station has a fairly short broadcast range, and this varies little with regard to day or night. The limited range of FM stations as compared to AM means that there is much less interference on the FM dial than for AM. In the United States and most other countries, one cannot simply broadcast at will; the airwaves are regulated, and, in America, the governing authority is the Federal Communications Commission (FCC). The FCC, established in 1934, was an outgrowth of the Federal Radio Commission, founded by Congress seven years earlier. The FCC actually sells air, charging companies a fee to gain rights to a certain frequency. Those companies may in turn sell that air to ot

Guitar Concert Critique

From Left to Right: Danica Rae Espiritu, Jerico S. Dela Cruz, Darla Denielle R. Felizardo, April Jane B. Luna, Judith D. Domingo, Angelo Gabriel I. Manila Last February 14, a guitar concert took place at the University of the Philippines Los Banos. The concert held in NCAS auditorium was entitled 12 strings with Nobel Queano and Franco Maigne as the artists. I. General Reaction a. Physical Setup Upon entering the auditorium, you will already feel the classy ambiance of the whole venue which matches perfectly with the music being played in the venue. Some members of the group have also some insights about the venue.According to Darla, the setup was stunning. She was impressed with the design of curtains and the lights. She also said that the dominance of the color red in the setup added to the Valentines ambiance, giving the audience that romantic and lovely feeling along with the sweet harmony and melody of the two guitars. For Jerico, he was also grateful with the lights in the even t but for him, he suggested that it will be better if the lights will be in sync with the rhythm of the music. For April, she felt that the venue was very sophisticated and made her feel at home. The lights also made the venue extra-special.Angelo felt that the stage was too rigid for some movements. The whole group agreed that the sound system was very good because there were no faulty errors on the whole duration of the concert. b. Personal Reaction Overall, it was really a great show. Although some students find it boring, majority in our group find the concert to be enjoyable and interesting. For Darla, she said that she definitely did not waste her 100 pesos for the ticket because the setup was beautiful, the artists were great, and the music being played was so relaxing. She also said that it was a good stress-reliever after a long day in class.For Angelo, he thought that the concert would be continuous with no breaks and that the artists would not be able to have some talking to the audience, but they did. He also said that the set of classical songs are so good that he almost felt the feeling of the one that composed the pieces. He also added that the addition of modern songs in the set list is great because it matches the audience’s genre. Danica was so amazed with how the artists play and handle the guitar but she felt that it was little boring to listen because she didn’t know most of the songs that were played. c. RepertoireIn terms of the artists’ set list, our group also agrees that they have a good set of songs. Although most of the songs played were not familiar, they really made an effort to make their pieces to be appreciated. According to Danica, you can really feel the love of the two artists to Spanish Music through their setlist. She also said that it was a good line up actually, because it was a combination of slow and upbeat music. She said that it was clearly a good picture for students like us what classical music really mean. For Jerico, he liked the set list because the artists included an opm which really made him appreciate the concert more.For Darla, although she didn’t know most of the songs that they played, she liked how the artists arranged their pieces and she felt like she was going through a timeline of music. II. One Favorite Composition Majority of the members in our group liked the â€Å"Super Mario Medley† which was composed by Koji Kondo for the game â€Å"Mario†. They liked it because of the arrangement done by the artists and even the little effects were given emphasize such as the melody when Mario shoots, when he grows, and when he shrink back to his original size. They felt that it was amusing and heartwarming and they left the audience craving for more.They also noticed that the elements of music such as melody, harmony, and rhythm changes accordingly to the parts of the medley they played. Also, even though they made their own arrangement for it, the people still recognized that it was the Super Mario theme. Overall, it was executed in a perfect way. Jerico on the other hand has a different favorite composition. His favorite composition was â€Å"Sana Maulit Muli† which was composed, arranged and sang by Mr. Gary Valenciano. He liked the sound of the song because of its varying dynamics.The harmony and the melody of the song makes it more appealing to the mass. Angelo also has another favorite; his favorite was â€Å"Love Story† which was sang by Taylor Swift. . He liked it because it is polyphony and it emphasizes fast tempo and repetitive melodic patterns. III. Performance a. Artists’ Skill in Playing the Instrument There is no doubt that the artists were really good. They play the instruments really really well. They handled the guitar almost perfectly that it seems that it was very easy and light to play. The displayed their talents in a very awesome way that they left the audience in awe.They were s o good in playing the guitars since the classical songs that they played were made for piano and orchestra, yet they managed to play those pieces perfectly. We were also amazed when they told us that the other one plays with his left hand while the other one plays with his right hand. Amazing indeed! Seeing them play makes us want to learn how to play the guitar as brilliant as them. b. Stage Presence and Audience Rapport In terms of stage presence, our group agreed that the artists have great stage presence. The crowd went crazy when they play familiar songs and the crowd often sings with the music and clap at each piece.The introduction of the song before they play it creates a connection between the audience and the artists making the audience really tuned into their performance. It is also good that they played two popular songs towards the end. They made sure that the audience can relate and sing along to the pieces that they performed. All in all, the concert was a great perfo rmance indeed. Love Story, which was the last song for that night was really perfect for Valentine’s Day. Overall, it was really and inspiring show. By watching the concert we learned to appreciate guitar and classical music even more.

The Rapid Economic Growth Trends Demonstrated By China,...

The rapid economic growth trends demonstrated by China and India are currently at the height of debate amongst world leaders and economists. According to â€Å"Dancing with Giants: China, India, and the Global Economy†, edited by L. Alan Winters and Shadid Yusuf (2007), these countries are very unique in that their economic patterns of growth continue to increase and sustain momentum over an extended period of time while dealing with growing populations. The fact that these countries have illustrated a sustained pattern of growth means that they are beginning to, or have already shifted the balance of power within the global community; however, many scientists believe that this trend has shown negative side effects within the social and political settings because inequalities within both regions continue to rise. In Dancing with Giants: China, India, and the Global Economy (2007) the author states that, â€Å"Chinese and Indian authorities face important challenges in keeping their investment climate favorable, their inequalities levels at intervals that do not undermine growth, and their air and water quality at acceptable levels† (8). In a discussion, I will deconstruct the effects of China and India’s economic growth on social inequalities. The effects that the economic growth trends and reforms in China have on the rising levels of social inequality have raised debates in the past and have resurfaced today. Some political scientists and economists argue that regionalShow MoreRelatedEffects Of China s Fiscal For The Australian Economy3915 Words   |  16 PagesEXTENDED ESSAY What are the effects of China’s recent economic slowdown in GDP for the Australian economy? Word Count â€Æ' ABSTRACT This essay looks to answer the question: What are the effects of China’s recent economic slowdown in GDP for the Australian economy? The intention is to look at China’s recent reduction in GDP rate of growth and find out if there are any significant negative implications for the Australian economy, and further investigate fears in the media that the slowdownRead MoreTurkey: The Second Largest External Supplier of Textiles and Clothing1933 Words   |  8 Pagesand apparel trade and production trends: the EU’ from the ‘Textile Outlook International’ article, focusing on Turkey as a country of interest when it comes to international trade. This will explore political, environmental and commercial forces apparent to Turkey’s success concluding with the outlook for the countries future. Introduction The value of EU clothing and textile exports to countries outside the EU has risen 13.3% from 2010 to 2011 which hints that global trade is increasing and expandingRead MoreIndia and China Comparative Economic Analysis5875 Words   |  24 PagesEconomic models of India and China: Looking back and looking ahead [5400 words] China and India are two of the world’s oldest civiliza ¬tions, each with the quality of resilience that has enabled it to survive and prosper through the ages and against the odds. Existing in close proximity to each other, the ancient civilizations of India and China surprisingly had little political and economic interac ¬tion for the past many centuries. Historically and culturally India never playedRead MoreExport Sophistication, Diversification And Product Space Evolution8487 Words   |  34 PagesAbstract By assessing the export sophistication, diversification and product space evolution, we discuss the reasons behind thirty years’ growth miracle of Chinese economy and causes of recent slowdown. Disaggregated export data dating back to 1985 is utilized to analyse the characteristics of China’s export basket especially its sophistication level and diversification degree. And China’s development path as constantly extending into production of new and more complex commodities is discussedRead MoreEssay on Londons Economy2305 Words   |  10 Pagesdissolution of empire has been critical to the growth of world cities. How far does this apply to London? Modern patterns of development and growth have been shaped and influenced by the historical context of colonialism. Within this context relationships between capitalist and pre-capitalist states or colonies helped forge a world economy, which would later lead to processes of globalisation and the current economic world order. Expansion in the world economy has been exacerbated by the freer flow Read Morecan india become a superpower Essay4304 Words   |  18 Pagesï » ¿CAN INDIA BECOME A SUPERPOWER Introduction: 1. The end of the Cold War and the era of â€Å"unipolar† US dominance that followed has led many to wonder about the future of international power. Who will rival, or perhaps even replace, the US? At least one†¦At least one obvious candidate has emerged. Although it would be premature to categorise China as a global superpower, it is quickly developing into the US’s most plausible challenger. But in discussions of globally important matters - SyriaRead MoreAnalysis Of The Poem A Planet Of Slums 2076 Words   |  9 Pagescentered around the world s dramatic population growth coupled with economic recessions resulting in cities made of dirt instead of dreams. These megaslums are literally taking the space of any rural areas left while also figuratively destroying the concept of the modern metropolis. Davis points out that in addition to merely running out of space for our ever growing Crude Birth Rate, the IMF and World Bank are to be blamed almost entirely for the economic state of these megaslums due to their insistanceRead MoreA Study On The Brazilian Performance2760 Words   |  12 Pages The topic of emerging economies has been hot over the past decade or so, most notably the emergence of the group of countries known as the BRICS nations (Brazil, Russia, India, China and South Africa). Growth rates in these economies far exceed that of more developed nations. In 2011-2013, BRICS economies posted average growth rates of 4.11% compared to 1.37% in developed economies (Lukov, 2010). By 2020 all BRICS should be in the top 10 largest economies in the world, and by 2050, they will beRead MoreEvolution of Human Resource Management7638 Words   |  31 PagesGUEST EDITORS’ INTRODUCTION GROWTH AND GLOBALIZATION: EVOLUTION OF HUMAN RESOURCE MANAGEMENT PRACTICES IN ASIA ARTHUR YEUNG, MALCOLM WARNER, AND CHRIS ROWLEY In this introductory note, we offer an overview of how human resource management in Asian countries and corporations is evolving in the face of rapid business growth and integration into the global economy and we describe how the articles in this Special Issue contribute to new knowledge and insights regarding key issues, challenges, and evolutionRead MoreThe Automotive Industry and Its Mitigation Strategies Essay1981 Words   |  8 PagesFor the last two years, the car industry has experienced constant changes in the world political conditions, economic climate, socio-cultural transformation and technological advancement. Today’s carmakers have been astonished by the increasingly growing demand in the developing world, and also struggled to meet all the demanding environmental regulations in most countries in the world. In addition, the new development of mega cities, and the emergence of new technologies have urged automakers to

Designing An E Commerce Solution Evaluation Essay

Contents Introduction†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ Types of E-commerce†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. E-commerce in use by organisations†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦... Financial implications†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. Designing an e-commerce solution†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ Evaluation†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. References†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ Introduction. Many businesses have shown that after implementing an e-commerce system into their companies, sales have increased immensely. Sneaker Joe’s is a small family run business that is looking to expand their business after the sneakers they sell have shown to be very popular locally, after a picture of them was spotted on a social networking site. I have been looking at some of the most popular websites that consumers use to purchase their goods and what kind of commerce system they have in place, but first, I have written an explanation of the different types of ecommerce used today. Types of Ecommerce. E-commerce is the process of buying and selling of various products and services by businesses through the Internet. Primarily there are five types of ecommerce systems: Business to Consumer (B2C) B2C stands for Business to Consumer as the name suggests, the basic concept of this model is to sell the product online to the consumers. B2C is the indirect trade between the company and consumers. It provides direct selling through online interaction.. Business toShow MoreRelatedSystem Analysis and Design1287 Words   |  6 Pagesimplementation – system evaluation – system modification. Role of systems analyst – attributes of a systems analyst – tools used in system analysis Module 3: Information gathering (3) Strategies – methods – case study – documenting study – system requirements specification – from narratives of requirements to classification of requirements as strategic, tactical, operational and statutory. Example case study Module 4: Feasibility analysis (3) Deciding project goals – examining alternative solutions – cost – benefitRead MoreEnterprise Resource Planning : Effective Communica tion And Proper Data Exchange Within Internal Departments Essay1059 Words   |  5 PagesPlanning The success of any business lies in effective communication and proper data exchange within internal departments. Delayed in latest information is a remarkable obstacle in failure of any business. To overcome this problem, a proficient solution ERP came into existence. The vast tool, capable of integrating internal business processes of any organization, is so called termed as Enterprise Resource Planning. ERP is an approach of amalgamating the various departments of an enterprise suchRead MoreWeb Interview Essay961 Words   |  4 Pages20 Questions to Ask Before Hiring Any Web Designing Company Planning to hire the best Web design and development company? Well, you need to read this article first before taking any step. Understand that the website acts as a window to provide an insight of your business to the customers. The website the web development company is going to design will play an important part in your company to achieve the desired marketing goals. Whether you are designing your website for the first time or revampingRead MoreIssues Plaguing Saudi Aramco Company886 Words   |  4 Pagesthem. Employees have no loyalty to the company. Solutions for Change Effort Insist that managers reconnect with their teams. Insist that managers develop their teams. Insist the managers improve their immediate work environments. Insist that managers engage in better more effective communication strategies. (mindtools, 2013) Offer goodies and gimmicks to regain employee interest at least temporarily (Lee, 2010). Watkins Performance Solution 1) identifying desired performance 2) definingRead MoreElectronic Payment Methods2299 Words   |  10 Pages Contents Introduction 3 Sizes of Electronic Payments 3 Electronic Means 3 Critical Issues 3 S.W.O.T Analysis 4 Problem Statement 5 Options 5 Recommendation 5 Feasible Solutions 6 Monitoring 6 Evaluation 7 References 8 Introduction Payment systems that use electronic distribution networks constitute a frequent practice in business sector, especially for banking industry. The term of electronic payments includes any paymentRead MoreInternet Banking: Reliability and Accessibility Issues4370 Words   |  18 Pagesgreater control of their accounts. Banks achieve cost and efficiency gains in a large number of operational areas. This paper addresses the aspects of reliability and accessibility from a banking enterprise point of view and puts forth present day solutions to problems involving these issues. An Indian perspective of Internet banking is also looked at in order to gaining a better perspective regarding the situation. Table of Contents 1. Introduction †¦ †¦ †¦ 3 2. Problem Description†¦Read MoreEssay on Digital Customer Engagement and Social Media2751 Words   |  12 Pageswith its potential to better serve customers and satisfy their needs (Sashi, 2012). Customer get engaged with e-commerce and m-commerce application with the use of internet which can be accessed through desktop, laptop, tablets, smart phones and PDA. Generally, e-commerce is deï ¬ ned as a monetary transaction conducted using the internet and a desktop or a laptop computer and M-commerce can be deï ¬ ned as a transaction that takes place through wireless internet-enabled technology (through laptops, mobileRead MoreErp Implementation Life Cycles Stages1677 Words   |  7 PagesLife cycle The ERP implementation life cycle consist of; ï‚ § Pre evaluation Screening ï‚ § Package evaluation ï‚ § Project planning phase ï‚ § Gap Analysis ï‚ § Reengineering ï‚ § Configuration ï‚ § Implementation team Training ï‚ § Testing ï‚ § Going Live ï‚ § End-User Training ï‚ § Post Implementation Pre-evaluation Screenings In order to develop a new ERP package the available packages should be evaluated before coming to the solution But this pre evaluation should be done with a chosen number of packages since there are hundredsRead MoreCloud Architecture Personal Statement Examples1095 Words   |  5 Pagesarchitectures including but not limited to: cloud architecture, systems architecture, service-oriented architecture, application architecture, web-based solutions, data architecture and security architecture. I possess extensive experience and skill in developing and implementing mobile solutions, big data, business intelligence and e-commerce. I have the ability, knowledge and skill to understanding and implement future trends and the ability to drive innovation justifying technology investmentsRead MoreBusiness Skills for E-Commerce6864 Words   |  28 PagesBusiness Skills for E-Commerce Group Assignment Executive summary The documentation is about the process of implementing an e-commerce solution for the Dinapala Group of company. As the first step of completion, a preliminary investigation has done about the selected organization in order to have a proper idea about the problem scope and the background. After identifying the circumstantial, organization’s core business functions have assesses under the outcome criteria of understanding