Electromagnetic Wave
1.Definition of Electromagnetic Waves.
Electromagnetic waves are waves that can propagate even though there is no medium. A magnetic field that changes with time can generate an electric field that also changes with time, and an electric field that changes with time can also produce a magnetic field. If the process is continuous it will produce a magnetic field and electric field continuously. If these magnetic fields and electric fields simultaneously propagate (spread) in space in all directions then this is a symptom of the wave. Such a wave is called an electromagnetic wave because it consists of an electric field and a magnetic field that travels in space.
Electromagnetic energy propagates in waves with several
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The higher the energy level in an energy source, the lower the wavelength of the energy produced, and the higher the frequency. Differences in wave energy characteristics are used to classify electromagnetic energy.
Electromagnetic waves are factors of wavelength, frequency and speed of electromagnetic wave propagation or the relationship between rapid propagation of vapors that can propagate in a vacuum by multiplying the wavelength and its frequency. Equation of Electromagnetic Waves The equation is:
V =
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Wire time (or panghantar such as an antenna) conducts alternating current, electromagnetic radiation is propagated at the same frequency as the electric current. Depending on the situation, electromagnetic waves can be waves or like particles. As a wave, characterized by speed (speed of light), wavelength, and frequency. When considered as particles, they are known as photons, and each has an energy associated with the frequency of the waveform shown by the Planck relationship E = Hν, where E is the photon energy, h is the Planck constant - 6.626 × 10 -34 J · s - and ν is the frequency of the
through space. This theory came to life when Heinrich Hertz created those waves and seven
Radio is device that use technology of using radio waves to transfer information, such as sound, by using the properties of electromagnetic energy waves transmitted through space, such as their phase, amplitude, frequency, or pulse width. If radio waves passing an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be get back into its original form.
Light is both part particle and part wave. Light is “the electromagnetic radiation that may be perceived by the human eye”. It consists of photons, which are massless bundles of concentrated electromagnetic energy. Light’s lower frequency is red, and the higher frequency is blue. Like sound, light has frequencies humans can’t detect. Ultraviolet light is at a frequency higher than violet, and infrared is at the frequency lower than the red of visible light. We get UV (ultraviolet) rays from the sun, and infrared is used in night vision to see better.
X-rays and gamma ray photons are part of the electromagnetic spectrum. The twin nature of electromagnetic radiation is used to justify the wave and its behavior. A photon is a bundle of energy that can be identified by the equation E = hv. Where h is the planks constant and v is the frequency. The frequency is equal to the speed of light 3x10 8 divided by the wavelength. Therefore, high-energy radiations have a short wavelength and a high frequency.
Radio-wave technology is one of the most important technologies used by man. It has forever changed the United States and the world, and will continue to do so in the future. Radio has been a communications medium, a recreational device, and many other things to us. When British physicist James Clerk Maxwell published his theory of electromagnetic waves in 1873, he probably never could have envisioned the sorts of things that would come of such a principle. His theory mainly had to do with light waves, but fifteen years later, a German physicist named Heinrich Hertz was able to electrically generate MaxwellÕs ÒraysÓ in his lab. The discovery of these amazing properties, the later invention of a working wireless radio, and the resulting technology have been instrumental to AmericaÕs move into the Information Age. The invention of radio is commonly credited to Guglielmo Marconi, who, starting in 1895, developed the first ÒwirelessÓ radio transmitter and receiver. Working at home with no support from his father, but plenty from his mother, Marconi improved upon the experiments and equipment of Hertz and others working on radio transmission. He created a better radio wave detector or cohere and connected it to an early type of antenna. With the help of his brothers and some of the neighborhood boys he was able to send wireless telegraph messages over short distances. By 1899 he had established a wireless communications link between England and France that had the ability to operate under any weather conditions. He had sent trans-Atlantic messages by late 1901, and later won the Nobel prize for physics in 1909. Radio works in a very complicated way, but hereÕs a more simple explanation than youÕll get from most books: Electromagnetic waves of different wavelengths are produced by the transmitter, and modulations within each wavelength are adjusted to carry ÒencodedÓ information. The receiver, tuned to read the frequency the transmitter is sending on, then takes the encoded information (carried within the wave modulations), and translates it back into the sensory input originally transmitted. Many of the men who pioneered radio had designs for it. Marconi saw it as the best communication system and envisioned instant world-wide communication through the air. David Sarnoff ( later the head of RCA and NBC) had a vision of Òa radio receiver in every homeÓ in 1916, although the real potential of radio wasnÕt realized until after World War I.
Music is transmitted through sound waves, which are very similar to the sine waves studied in Trigonometry. The differences in the waves result in a different sounds that are transmitted. Vibrating objects travel through a medium (the material that the disturbance is moving through) to create sounds at a given frequency. The frequency is how often the particles vibrate when a wave passes through the medium. The unit that is most used to measure frequencies is the Hertz (Hz) and 1 Hz is equivalent to 1 vibration per second. The frequency affects the pitch of the note that is being played; The higher the frequency the higher the pitch and the lower the frequency the lower the pitch.
In an electromagnetic wave, the constantly changing electric and magnetic fields affect each other so they both oscillate in different axis while the wave moves in a direction perpendicular to the oscillation of the fields as shown in Figure 1.
Nature of wave: It is an electromagnetic wave as it does not necessarily require a medium for p...
First off, what is current. Current is expressed in a unit called Amps. Amps are a measurement of how many electrons pass per second. That is to say, a wire with 40 coulombs passing any point in a 2 seconds would be said to have 20 Amps of current (40 Coulombs (a unit of charge given as 6.24x1018 electrons) / time in seconds or in this case, 2 seconds. The Amp is also known as Coulombs per second) Another trick about current is that it is measured in the movement of the positive charge. Literally that is to say the current moves in oppostion to the electrons. This is because originally it was thought that the positive charge is what moved, both are viable, but in reality a positive charge is generally fixed since within an atom the electrons are migratory, while the protons and neutrons tend to be stationary.
Sound waves take the form of compressional waves and are caused by vibrations. Sound waves are distinguished by their speed, pitch, loudness and quality (timbre) (Lapp, 2003). There are a few parts of sound waves that we should be familiar with to better be able to understand the physics of music. The crest is the highest point of a wave, while the trough is the lowest. The wavelength of a wave is the distance between two adjacent parts of a wave, like from crest to crest, or from trough to trough....
The history of engineering goes back into the 19th century when Alexander Volta (1745-1827) made a remarkable discover regarding the nature of electricity (Cosgrove 749). He discovered that electrical current could be controlled and could flow from one point to another. By the time the mid-19th century came about the rules for electricity were being established. During this time electromagnetic induction was discovered by Michael Faraday who lived from 1791 to 1867 (749). Also during this time Samuel Morris invented the telegraph in 1837 which relies on the principles of electromagnetic induction (749). Alexander Graham Bell, who lived from 1847 to 1922, created the telephone which also uses electricity in order to operate (749). Through the success of the telephone, Bell Telephone Company was established. In 1878, the light bulb was finally invented by Thomas Edison who lived from 1847 to 1931 (749). Off the principles of Faraday’s electric motor from 1821, Nicholas Tesla invented a more efficient and powerful electric motor in 1888 (749). To make these inventions be more significant, effort was expended to make better motors and transformers and to enhance the power needed to make them function. Through these inventions during the middle 19th century, it led to the capability of lighting homes and cities through the use of electricity, and it also led to the creation of the telephone communication system (750).
The phenomenon called electromagnetic induction was first noticed and investigated by Michael Faraday, in 1831. Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing magnetic field about the conductor and is a very important concept. Faraday discovered that, whenever the magnetic field about an electromagnet was made to grow and collapse by closing and opening the electric circuit of which it was a part, an electric current could be detected in a separate conductor nearby. Faraday also investigated the possibility that a current could be produced by a magnetic field being placed near a coiled wire. Just placing the magnet near the wire could not produce a current. Faraday discovered that a current could be produced in this situation only if the magnet had some velocity. The magnet could be moved in either a positive or negative direction but had to be in motion to produce any current in the wire. The current in the coil is called an induced current, because the current is brought about (or “induced”) by a changing magnetic field (Cutnell and Johnson 705). The induced current is sustained by an emf. Since a source of emf is always needed to produce a current, the coil itself behaves as if it were a source of emf. The emf is known as an induced emf. Thus, a changing magnetic field induces an emf in the coil, and the emf leads to an induced current (705). He also found that moving a conductor near a stationary permanent magnet caused a current to flow in the wire as long as it was moving as in the magnet and coiled wire set-up.
Electromagnetic radiation is energy that flows through free space. Electromagnetic radiation comes in a list of energies known as the electromagnetic spectrum. Electromagnetic spectrum is the complete range of the different wavelength of electromagnetic radiation. It consists of light, radio waves, visible light, infrared waves, ultraviolet light, x-rays, microwaves and gamma rays.
waves are further divided into two groups or bands such as very low frequency (