Electromagnetic Induction
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.
Faraday visualized a magnetic field as composed of many lines of induction, along which a small magnetic compass would point. The aggregate of the lines intersecting a given area is called the magnetic flux. Faraday attributed the electrical effects to a changing magnetic flux.
The necessity of motion to produce a current is due to the fact that electromagnetic induction involves a time-varying magnetic field. The same effects can be produced by moving the coil toward and away from a motionless magnetic source. In either case, the key to producing the current is certainly the motion of the magnet or the wire. The magnetic lines of the magnetic field must pass through a loop of the coiled wire.
The major encounters that Tesla and Faraday faced included social, economic, intellectual barriers. Considering socially, Faraday was considered to be a “...high-priest of Nature, revealing the hidden forces...”(Shortland) People saw Faraday as the highest of his field, the one who was the closest to God in relation to understanding his creation. This also shows the social standard at this point in time, many going to church and understanding when someone references a religious point. Also, for social encounters, we have Tesla with his description f what the future will be like. This was not a reaction to the society that Tesla was around, but a prediction of what they were to become. Tesla, hoping to see that people would grow to become stronger
As we read through the memoir A Long Way Gone by Ishmael Beah, there are many striking moments or key passages that have a lot of meaning, character development, or plot development. These key moments occur at many times, such as before Ishmael is a soldier, during Ishmael’s time as a soldier, and during rehabilitation from being a soldier. The three most striking of key passages from the book that are important to character development, plot development, and meaning is when Ishmael learned to be more independent, when war and killing becomes a daily part of Ishmael’s life, and the theme of revenge causes more revenge.
... instill the violent act of killing in the minds of the child soldiers. Ishmael learns that he must channel his rage and seek revenge for the death of his family. From this, Ishmael and many other young soldiers now believed that revenge was the only way to fight for what they have lost. It is because of this violent filled society that Ishmael and other young soldiers suffered from a disorder called Post Traumatic Stress Disorder. PTSD is a mental condition that occurs as a result of a psychological shock, which in this case is the war. As Ishmael was being pulled out of the corruption he was living in, it was at this time that readers realized that he was suffering from PTSD, and was going to receive help in order to correct it. All in all, it is the manipulation and misuse of the power of authority that impacts innocent young soldiers in a psychological manner.
To understand how this motor works, we must understand the relationship between electricity, and magnetism, or simply put, electromagnetism. Direct electric current in a simple description: There are two requirements for current flow. The first is a source of electrical potential energy or EMF (electro motive force). The second is a conductor that provides a complete loop to carry the current. The reason a conductor will conduct is found at the atomic level.
In some Greek experiments, objects attracted each other after rubbing. Other experiments produced objects that pushed away, or repelled, each other. The evidence showed that electric force made matter either attract or repel other matter.
Cheating on academic work is a serious issue that most students admit to doing at some point in their academic career. Elite students are surprisingly the culprits of cheating, but hide it well. (Romm, para 5) Cheating is such a large issue that “70% of students from a sample of 1,800 from nine campuses said they had cheated at least once during their college careers.” (Schneider, para 9) Students cheat on academic work because of different, ongoing pressures in their lives. Understanding the student’s motives and pressures are essential to preventing cheating from occurring in the future. Students cheat for different reasons specific to them regarding their priorities, pressures and because of how easy it has become. Even though eliminating cheating will not happen, there are actions that educational professionals can and should take to prevent most of it from happening so often. Therefor cheating problems are minimized and have a positive impact on the student’s education and understanding of concepts.
Modern students face many pressures for academic success. They are often unwilling to disappoint their parents or spouses. Some fear that not cheating will weaken a student’s ability to compete with their peers. They rationalize their unethical behavior, unwilling to accept a poor grade, consequently justifying cheating as the only means to that end.
As a graduate student, I will undertake research and coursework in Electrical Engineering to enhance my competencies in this field. I intend to complete my master's degree in order to pursue my doctorate. The research that I am most interested in pursuing at Northeastern University surrounds the optical properties of MEMS devices, and the development of substrate-based fast electro-optical interfaces. My interest in this area stems from my undergraduate study in MEMs development for tri-axial accelerometers.
Electrical Engineers research, develop, design, and test electronic components, products, and systems for commercial, industrial, medical, military, and scientific applications (Cosgrove 749). They are concerned with devices that use small amounts of electricity that make up electronic components such as integrated circuits and microprocessors. By applying principles and techniques of electronic engineering they design, develop, and manufacture products such as computers, telephones, radios, and stereo systems (EGOE, 121). Electrical engineers touch everyone lives through the things they have designed or created. Electrical engineers have invented the lights in your house, the television, the stereo, the telephone, computers, and even your doctor’s blood pressure gauge (Stine 300).
When the generated fields pass through magnetic materials which themselves contribute internal magnetic fields, ambiguities can arise about what part of the field comes from the external currents and what comes from the material itself. It is common to define another magnetic field quantity, usually called the "magnetic field strength" designated by H. It can be defined by the relationship, H = B0/μ0 = B/μ0 – M, and has the value of unambiguously designating the driving magnetic influence from external currents in a material, independent of the material's magnetic response. The relationship for B can be written in the equivalent form, B = μ0(H + M), H and M will have the same units, amperes/meter. To further distinguish B from H, B is sometimes called the magnetic flux density or the magnetic
Humans these days take electricity for granted. We don’t truly understand what life was like without it. Most young adults will tell you their life does not depend on electricity, but they aren’t fooling anyone. They all know that their life depends on electricity; whether it’s television, their phone, Google, or the lights in their house. We need to stop taking those things for granted and give credit where credit is due. That is why I chose to write about the scientists who contributed to the discovery of electricity, which then helped modern scientists fuel the electricity phenomenons we now have today.
Faraday built two devices to produce what he called electromagnetic rotation: that is a continuous circular motion from the circular magnetic force around a wire. Ten years later, in 1831, he began his great series of experiments in which he discovered electromagnetic induction. These experiments form the basis of modern electromagnetic technology.
The effects of electricity control much of our daily lives. Many of our gadgets and everyday tasks are run by this wonderful source of power. For example without electricity we would not be able to make a cup of coffee in the mourning, or even make a long distance call to family or friends. There have been several technological breakthroughs by many brilliant people throughout history regarding electricity. It has come from being discovered as a small current to being transformed into useful power to run such things as computers. Ben Franklin, Guglielmo Marconi, Thomas Edison, Paul Nipkow, and Charles Babbage have all contributed to the advancement of electricity, and all of their advancements have supplied society in many ways.
Usually magnetic fields are created when an electric current is applied to a set of conductive wires wound together (Dixon, 2001). Magnetic fields can also be created using Permanent Magnets (PM). Electrical motors can also work as electrical generators (Correla, 1986). Electrical generators are devices capable of converting mechanical energy into electrical energy. An example would be a wind turbine which works as an electrical generator.
...placing a soft metal core (commonly an iron alloy) inside a coil of wire through which electric current passes in order to produce a magnetic field. The strength and polarity of the magnetic field changes depending on the magnitude of the current flowing through the wire and the direction of the current flow. While there is sufficient flow of current, the core behaves like a magnet; however, as soon as the current stops, the magnetic properties also disappear. Modern devices that make use of electromagnets are the televisions, telephones, computers and electric motors.