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However, for the foreseeable future PH, the introductory electromagnetism course, will be delivered in the main physics building, Meyer Hall, which was designed in specifically for the lecture-lab-recitation format and has not undergone significant renovation since. However, we do not consider the absence of an IT-integrated laboratory for PH to be a major impediment. Students entering PH bring a mechanical intuition that is readily exploited using sensors and computers to bridge the familiar phenomena of motion with their mathematical and graphical representations.

The use of a "black box" to bridge the phenomenon and its representation creates no conceptual hurdles when dealing with the familiar. This contrasts sharply with PH where student intuition about electromagnetic fields and concepts is largely absent. This explains in part why electromagnetism is notoriously difficult for beginning engineering students to master - they bring little or no prior understanding.

In Vygotskian terms there is little upon which to build a "zone of proximal development" - an area of cognitive performance achievable with assistance. Perhaps making a virtue of a necessity, we believed it important therefore to use the laboratory as an opportunity to ground the students' introduction to electromagnetic concepts directly and as firmly as possible in the familiar mechanics concepts of force and energy. We have eschewed the use of black-box interfacing equipment, and computers were used only to assist in numerical analysis of the data using a spreadsheet.

The energy foundations of the electric potential are reinforced in Laboratory III The Energy of a Capacitor in which electrical energy is converted to heat. Following the ZAP! They see electric or magnetic forces move objects, test their circuits by touching the low current high voltage output, see and hear the electric discharge as air is broken down, search for a hidden object with a metal detector, and calibrate a thermometer by placing the thermistor element in their mouths.

Thus, there are 7 PH laboratories in a 15 week semester. In the non-laboratory week the students participate in a 2-hour problem-solving recitation. Thus, the plan is to continue with the alternate week mode for now which, while not ideal, is effective and manageable within existing resources. Each laboratory station is equipped with a computer, a storage bin with tools, wire, components, and miscellaneous parts , a multimeter, a low voltage power supply, an oscilloscope, and a function generator. This is supplemented for each lab with the necessary specialized equipment such as a knife-edge balance and custom circuit boards.

The roles are rotated each lab, but we find that students tend to fall into specific roles despite our best efforts otherwise. This exercise is important to the integration of the lecture topics with the laboratory's design activity since the analysis is based on current lecture topics. We make extensive use of spreadsheets to perform the numerical calculations and error analysis for the labs.

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Although many students have some experience with spreadsheets, they are not expected to have this skill at the start; so the first lab devotes time to teaching basic spreadsheet skills. For each lab we provide a spreadsheet template which varies from almost completely preprogrammed in the first lab to virtually empty by the last lab. To save time the lab manual has a workbook section that is filled out by the recorder and turned in at the conclusion of the lab along with a printout of the team's spreadsheet.

The laboratories are team graded. We have experimented with assigning teams using PH grades, forming teams with high, middle, and low achieving students, but we have not been able to measure any effect from this. An important secondary learning objective of PH is to introduce the students to engineering design experiences relating to electromagnetism. ABET defines "design" as the creative application of science and mathematics to the solution of practical problems 1. Elements of design include the establishment of objectives and criteria, synthesis, analysis, construction, testing, and evaluation.

While a full design experience is not feasible in a closed 3-hour lab, elements of design activities can be incorporated into the procedures.

Electromagnetism (FYTB13)

We align the content learning objectives with design experiences by requiring the students to use the fundamental physics topic under study in the lecture portion to guide the design and fabrication of critical components for the specific laboratory. Table I lists the seven experiments along with the physics principles and concepts illustrated, experimental objectives and design activities. Many of these experiments were adapted from ZAP!

Pine, J. In the ZAP! In particular, the students are required to solder all the required circuitry. While intensively hands-on, this time-consuming activity is not well aligned with other course learning objectives required in an integrated approach. A given ZAP! The design and fabrication activities are well-aligned with ABET design criteria, but the nontraditional delivery mode was not acceptable for our course.

The principal adaptation was to create special circuit boards where those components not related to the physics principles under study were prefabricated, saving time on these secondary activities. The students installed, designed, or fabricated only those few components that directly reinforced the physics lessons. This saving in fabrication time no doubt reduced the eventual technical skill level of the students, yet with a limited and fixed time budget, we felt this a reasonable and necessary compromise. Due to space limitations we discuss in some depth just three of the adapted laboratories to illustrate how elements of design aligned with course learning objectives are incorporated into the activities.

Detailed technical descriptions of the experiments will be presented elsewhere. It occurs in the sixth week when Ohm's Law and DC circuits are covered in the lectures. Capacitors and energy storage were covered previously. The basic idea is to use a metered bridge circuit with a themistor as one of the resistor elements to measure temperature, a familiar use of the bridge circuit.

The device is calibrated at room temperature and at body temperature obtained by placing the thermistor -covered with transparent tape- in one's mouth. The energy of a charged capacitor is measured by discharging it through the thermistor and quickly measuring its temperature change which, when multiplied by the thermistor's heat capacity, determines the energy. To fit into a standard 3-hour laboratory format a custom circuit board was created with the meter, potentiometer, and double-pole double-throw switch prewired as shown in Figure 1.

Since the electromagnetic lessons under study are Ohm's Law, electrical energy, and the effect of temperature on electrical conductivity, the students construct or connect those portions of the circuit dealing with those lessons: the thermistor side of the bridge circuit, the capacitor, the batteries, and power supply. The final circuit is virtually identical to that of ZAP!. The students construct and calibrate their instrument and then use it to determine the value of an unknown capacitor by measuring the energy it stores at a fixed voltage.

The resulting balance is awkward to use and not particularly accurate. This laboratory occurs in week eight after the students have learned about magnetic forces and during the Biot-Savart Law segment.

Electromagnetic Waves and Human Health

Our adaptation is to provide a custom knife-edge balance, shown in Figure 2, which is easy to use and quite sensitive. This balance has the novel feature of having the two knife-edges electrically isolated; so current can pass to beam through the knife-edge contacts. This avoids the need of having external wires connecting to the coil on the balance beam that can introduce unwanted torque.

In their pre-laboratory assignment using lecture-based concepts the students use the Biot-Savart and magnetic force laws to calculate the number of turns needed to produce a given force constrained by a current limitation and the balance sensitivity. During the laboratory, the students construct and install their coils, and then calibrate the balance using a fixed mass. The assessment for this laboratory has the students determine an unknown mass using their magnetic balance. In our adaptation we extend the induction concept to application by having the students construct a metal detector which adds greater relevance to their work in addition to a design activity.

This laboratory occurs in week ten after the students have studied the Biot-Savart Law and are concurrently studying Faraday's Law. As part of the pre-laboratory assignment, the students use the Biot-Savart and Faraday Laws to determine the number of turns needed for the field and pick-up coils of their metal detectors to meet a specified output voltage criterion subject to realistic size constraints.

During the laboratory, they construct and test the coils, recalculating and redoing their work if necessary. An additional secondary goal of the laboratories is to introduce technological applications of electromagnetic concepts to maintain interest and provide additional relevance. Those circuit components and connections not related to the electromagnetic lessons, such as the operational amplifier connections and the rectifying circuit, are prefabricated.

Figure 3 shows the custom circuit board and the metal detector layout. The students connect the field coil to a function generator related to the Biot-Savart Law , install the feedback potentiometer related to Ohm's Law application , and attach the metal detector's pick up coil to the amplifier input related to Faraday's Law. The prefabricated rectifying circuit provides a sensitive DC output that can be read on a digital multimeter.

The principal modifications from the ZAP! Then in a second stage, your group will be assigned another group's report and asked to give a brief critique assessment using — words half an A4 page of typeset text , where you review and assess the factual content of the report of the other group. Also the assessment is to be uploaded as a PDF. See precise assignment description for the assessment below.

Electromagnetic Waves

The deadline for handing in the report for your project is Mon, Oct 22 at On Wed, Oct 24, at , the assessment assignments will be published on L L. The deadline for submitting your assessment is on Wed, Oct 31, at At the same time for such a short text it is hardly necessary to use subsections. Use figures for illustration when trying to explain more complicated relations. This will help the reader to understand better.

Since the aim of the projects is to describe a modern application of electromagnetism you should include connections to electromagnetism when possible, using equations etc. Of course this will vary from project to project, since the connections vary. Sometimes the first three letters of the first author and the year of publication are used, for example [Hig64],. It is important to formulate the report with your own words. The text will be checked using Urkund. Spelling mistakes and grammatical errors will distract the reader from the content. In addition, saying the same thing several times using slightly different wording will tend to annoy the reader,.

Long, complicated sentences with lots of commas can throw the reader off course,. On Wednesday, Oct 24, your group will be asked to review and assess the factual content of the report of one of the other groups, using — words about half an A4 page of typeset text. The conductor offers a certain resistance, akin to friction, to the displacement of electricity, and heat is developed in the conductor, proportional to the square of the current as already stated herein , which current flows as long as the impelling electric force continues.

This resistance may be likened to that met with by a ship as it displaces in the water in its progress. The resistance of the dielectric is of a different nature and has been compared to the compression of multitudes of springs, which, under compression, yield with an increasing back pressure, up to a point where the total back pressure equals the initial pressure. When the initial pressure is withdrawn the energy expended in compressing the "springs" is returned to the circuit, concurrently with the return of the springs to their original condition, this producing a reaction in the opposite direction.

Consequently, the current due to the displacement of electricity in a conductor may be continuous, while the displacement currents in a dielectric are momentary and, in a circuit or medium which contains but little resistance compared with capacity or inductance reaction, the currents of discharge are of an oscillatory or alternating nature. Maxwell extended this view of displacement currents in dielectrics to the ether of free space.

Assuming light to be the manifestation of alterations of electric currents in the ether, and vibrating at the rate of light vibrations, these vibrations by induction set up corresponding vibrations in adjoining portions of the ether, and in this way the undulations corresponding to those of light are propagated as an electromagnetic effect in the ether. Maxwell's electromagnetic theory of light obviously involved the existence of electric waves in free space, and his followers set themselves the task of experimentally demonstrating the truth of the theory.

By , he presented the Remarks on the mathematical classification of physical quantities. In , the German physicist Heinrich Hertz in a series of experiments proved the actual existence of electromagnetic waves , showing that transverse free space electromagnetic waves can travel over some distance as predicted by Maxwell and Faraday. Hertz published his work in a book titled: Electric waves: being researches on the propagation of electric action with finite velocity through space. The electron as a unit of charge in electrochemistry was posited by G. Johnstone Stoney in , who also coined the term electron in It has been noted herein that Dr.

William Gilbert was termed the founder of electrical science. This must, however, be regarded as a comparative statement. Oliver Heaviside was a self-taught scholar who reformulated Maxwell's field equations in terms of electric and magnetic forces and energy flux, and independently co-formulated vector analysis. During the late s a number of physicists proposed that electricity, as observed in studies of electrical conduction in conductors, electrolytes, and cathode ray tubes , consisted of discrete units, which were given a variety of names, but the reality of these units had not been confirmed in a compelling way.

However, there were also indications that the cathode rays had wavelike properties. Faraday, Weber , Helmholtz , Clifford and others had glimpses of this view; and the experimental works of Zeeman , Goldstein , Crookes, J.

1. Introduction

Thomson and others had greatly strengthened this view. Weber predicted that electrical phenomena were due to the existence of electrical atoms, the influence of which on one another depended on their position and relative accelerations and velocities. Helmholtz and others also contended that the existence of electrical atoms followed from Faraday's laws of electrolysis , and Johnstone Stoney, to whom is due the term "electron", showed that each chemical ion of the decomposed electrolyte carries a definite and constant quantity of electricity, and inasmuch as these charged ions are separated on the electrodes as neutral substances there must be an instant, however brief, when the charges must be capable of existing separately as electrical atoms; while in , Clifford wrote: "There is great reason to believe that every material atom carries upon it a small electric current, if it does not wholly consist of this current.

In , J. He made good estimates of both the charge e and the mass m, finding that cathode ray particles, which he called "corpuscles", had perhaps one thousandth of the mass of the least massive ion known hydrogen. He further showed that the negatively charged particles produced by radioactive materials, by heated materials, and by illuminated materials, were universal.

The nature of the Crookes tube " cathode ray " matter was identified by Thomson in In the late 19th century, the Michelson—Morley experiment was performed by Albert A. Michelson and Edward W. Morley at what is now Case Western Reserve University. It is generally considered to be the evidence against the theory of a luminiferous aether. The experiment has also been referred to as "the kicking-off point for the theoretical aspects of the Second Scientific Revolution.

Dayton Miller continued with experiments, conducting thousands of measurements and eventually developing the most accurate interferometer in the world at that time. Miller and others, such as Morley, continue observations and experiments dealing with the concepts. By the end of the 19th century electrical engineers had become a distinct profession, separate from physicists and inventors. They created companies that investigated, developed and perfected the techniques of electricity transmission, and gained support from governments all over the world for starting the first worldwide electrical telecommunication network, the telegraph network.

William Stanley made the first public demonstration of a transformer that enabled commercial delivery of alternating current in Gordon , [] [ non-primary source needed ] in Lord Kelvin and Sebastian Ferranti also developed early alternators, producing frequencies between and hertz. After , polyphase alternators were introduced to supply currents of multiple differing phases. The possibility of obtaining the electric current in large quantities, and economically, by means of dynamo electric machines gave impetus to the development of incandescent and arc lighting.

Until these machines had attained a commercial basis voltaic batteries were the only available source of current for electric lighting and power. The cost of these batteries, however, and the difficulties of maintaining them in reliable operation were prohibitory of their use for practical lighting purposes.

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The date of the employment of arc and incandescent lamps may be set at about Even in , however, but little headway had been made toward the general use of these illuminants; the rapid subsequent growth of this industry is a matter of general knowledge. Such batteries are now utilized on a large scale as auxiliaries to the dynamo machine in electric power-houses and substations, in electric automobiles and in immense numbers in automobile ignition and starting systems, also in fire alarm telegraphy and other signal systems.

In , the World's Columbian International Exposition was held in a building which was devoted to electrical exhibits. General Electric Company backed by Edison and J. Morgan had proposed to power the electric exhibits with direct current at the cost of one million dollars. However, Westinghouse proposed to illuminate the Columbian Exposition in Chicago with alternating current for half that price, and Westinghouse won the bid.

It was an historical moment and the beginning of a revolution, as George Westinghouse introduced the public to electrical power by illuminating the Exposition. The Second Industrial Revolution, also known as the Technological Revolution, was a phase of rapid industrialization in the final third of the 19th century and the beginning of the 20th. Along with the expansion of railroads , iron and steel production, widespread use of machinery in manufacturing, greatly increased use of steam power and petroleum , the period saw expansion in the use electricity and the adaption of electromagnetic theory in developing various technologies.

The s saw the spread of large scale commercial electric power systems, first used for lighting and eventually for electro-motive power and heating. Systems early on used alternating current and direct current. Large centralized power generation became possible when it was recognized that alternating current electric power lines could use transformers to take advantage of the fact that each doubling of the voltage would allow the same size cable to transmit the same amount of power four times the distance.

Transformer were used to raise voltage at the point of generation a representative number is a generator voltage in the low kilovolt range to a much higher voltage tens of thousands to several hundred thousand volts for primary transmission, followed to several downward transformations, for commercial and residential domestic use.

The International Electro-Technical Exhibition of featuring the long distance transmission of high-power, three-phase electric current. As a result of this successful field trial, three-phase current became established for electrical transmission networks throughout the world. Much was done in the direction in the improvement of railroad terminal facilities, and it is difficult to find one steam railroad engineer who would have denied that all the important steam railroads of this country were not to be operated electrically.

In other directions the progress of events as to the utilization of electric power was expected to be equally rapid. In every part of the world the power of falling water, nature's perpetual motion machine, which has been going to waste since the world began, is now being converted into electricity and transmitted by wire hundreds of miles to points where it is usefully and economically employed. The first windmill for electricity production was built in Scotland in July by the Scottish electrical engineer James Blyth.

History of electromagnetic theory - Wikipedia

Brush , [] [ non-primary source needed ] this was built by his engineering company at his home and operated from until The connected dynamo was used either to charge a bank of batteries or to operate up to incandescent light bulbs , three arc lamps, and various motors in Brush's laboratory. The machine fell into disuse after when electricity became available from Cleveland's central stations, and was abandoned in Various units of electricity and magnetism have been adopted and named by representatives of the electrical engineering institutes of the world, which units and names have been confirmed and legalized by the governments of the United States and other countries.

Thus the volt, from the Italian Volta, has been adopted as the practical unit of electromotive force, the ohm, from the enunciator of Ohm's law, as the practical unit of resistance; the ampere , after the eminent French scientist of that name, as the practical unit of current strength, the henry as the practical unit of inductance, after Joseph Henry and in recognition of his early and important experimental work in mutual induction.

Dewar and John Ambrose Fleming predicted that at absolute zero , pure metals would become perfect electromagnetic conductors though, later, Dewar altered his opinion on the disappearance of resistance believing that there would always be some resistance. Walther Hermann Nernst developed the third law of thermodynamics and stated that absolute zero was unattainable. Carl von Linde and William Hampson , both commercial researchers, nearly at the same time filed for patents on the Joule—Thomson effect.

Linde's patent was the climax of 20 years of systematic investigation of established facts, using a regenerative counterflow method. Hampson's design was also of a regenerative method. The combined process became known as the Linde—Hampson liquefaction process. Heike Kamerlingh Onnes purchased a Linde machine for his research. Around , Karol Olszewski and Wroblewski predicted the electrical phenomena of dropping resistance levels at ultra-cold temperatures.

Olszewski and Wroblewski documented evidence of this in the s. A milestone was achieved on 10 July when Onnes at the Leiden University in Leiden produced, for the first time, liquified helium and achieved superconductivity. In , William Du Bois Duddell develops the Singing Arc and produced melodic sounds, from a low to a high-tone, from this arc lamp. Between and , many scientists like Wilhelm Wien , Max Abraham , Hermann Minkowski , or Gustav Mie believed that all forces of nature are of electromagnetic origin the so-called "electromagnetic world view".

This was connected with the electron theory developed between and by Hendrik Lorentz. Lorentz introduced a strict separation between matter electrons and the aether, whereby in his model the ether is completely motionless, and it won't be set in motion in the neighborhood of ponderable matter. Contrary to other electron models before, the electromagnetic field of the ether appears as a mediator between the electrons, and changes in this field can propagate not faster than the speed of light. In , three years after submitting his thesis on the Kerr effect , Pieter Zeeman disobeyed the direct orders of his supervisor and used laboratory equipment to measure the splitting of spectral lines by a strong magnetic field.

Lorentz theoretically explained the Zeeman effect on the basis of his theory, for which both received the Nobel Prize in Physics in This theorem states that a moving observer relative to the ether makes the same observations as a resting observer. This theorem was extended for terms of all orders by Lorentz in Lorentz noticed, that it was necessary to change the space-time variables when changing frames and introduced concepts like physical length contraction to explain the Michelson—Morley experiment, and the mathematical concept of local time to explain the aberration of light and the Fizeau experiment.

That resulted in the formulation of the so-called Lorentz transformation by Joseph Larmor , and Lorentz , He declared simultaneity only a convenient convention which depends on the speed of light, whereby the constancy of the speed of light would be a useful postulate for making the laws of nature as simple as possible. And finally in June and July he declared the relativity principle a general law of nature, including gravitation. He corrected some mistakes of Lorentz and proved the Lorentz covariance of the electromagnetic equations.

However, historians pointed out that he still used the notion of an ether and distinguished between "apparent" and "real" time and therefore didn't invent special relativity in its modern understanding. In , while he was working in the patent office, Albert Einstein had four papers published in the Annalen der Physik , the leading German physics journal.

These are the papers that history has come to call the Annus Mirabilis papers :. All four papers are today recognized as tremendous achievements—and hence is known as Einstein's " Wonderful Year ". At the time, however, they were not noticed by most physicists as being important, and many of those who did notice them rejected them outright. Some of this work—such as the theory of light quanta—remained controversial for years.

The first formulation of a quantum theory describing radiation and matter interaction is due to Paul Dirac , who, during , was first able to compute the coefficient of spontaneous emission of an atom. In the following years, with contributions from Wolfgang Pauli , Eugene Wigner , Pascual Jordan , Werner Heisenberg and an elegant formulation of quantum electrodynamics due to Enrico Fermi , [] physicists came to believe that, in principle, it would be possible to perform any computation for any physical process involving photons and charged particles. However, further studies by Felix Bloch with Arnold Nordsieck , [] and Victor Weisskopf , [] in and , revealed that such computations were reliable only at a first order of perturbation theory , a problem already pointed out by Robert Oppenheimer.

With no solution for this problem known at the time, it appeared that a fundamental incompatibility existed between special relativity and quantum mechanics. In December , the German chemists Otto Hahn and Fritz Strassmann sent a manuscript to Naturwissenschaften reporting they had detected the element barium after bombarding uranium with neutrons ; [] simultaneously, they communicated these results to Lise Meitner.

Meitner, and her nephew Otto Robert Frisch , correctly interpreted these results as being nuclear fission. Some historians who have documented the history of the discovery of nuclear fission believe Meitner should have been awarded the Nobel Prize with Hahn. Difficulties with the Quantum theory increased through the end of Improvements in microwave technology made it possible to take more precise measurements of the shift of the levels of a hydrogen atom , [] now known as the Lamb shift and magnetic moment of the electron. With the invention of bubble chambers and spark chambers in the s, experimental particle physics discovered a large and ever-growing number of particles called hadrons.

It seemed that such a large number of particles could not all be fundamental. Their assignment was to seek a solid-state alternative to fragile glass vacuum tube amplifiers. Their first attempts were based on Shockley's ideas about using an external electrical field on a semiconductor to affect its conductivity. These experiments failed every time in all sorts of configurations and materials. The group was at a standstill until Bardeen suggested a theory that invoked surface states that prevented the field from penetrating the semiconductor.

The group changed its focus to study these surface states and they met almost daily to discuss the work. The rapport of the group was excellent, and ideas were freely exchanged. As to the problems in the electron experiments, a path to a solution was given by Hans Bethe. In , while he was traveling by train to reach Schenectady from New York, [] after giving a talk at the conference at Shelter Island on the subject, Bethe completed the first non-relativistic computation of the shift of the lines of the hydrogen atom as measured by Lamb and Retherford.

The idea was simply to attach infinities to corrections at mass and charge that were actually fixed to a finite value by experiments. In this way, the infinities get absorbed in those constants and yield a finite result in good agreement with experiments. This procedure was named renormalization. Feynman's mathematical technique, based on his diagrams , initially seemed very different from the field-theoretic, operator -based approach of Schwinger and Tomonaga, but Freeman Dyson later showed that the two approaches were equivalent.

Even though renormalization works very well in practice, Feynman was never entirely comfortable with its mathematical validity, even referring to renormalization as a "shell game" and "hocus pocus". Peter Higgs , Jeffrey Goldstone , and others, Sheldon Glashow , Steven Weinberg and Abdus Salam independently showed how the weak nuclear force and quantum electrodynamics could be merged into a single electroweak force. Robert Noyce credited Kurt Lehovec for the principle of p—n junction isolation caused by the action of a biased p-n junction the diode as a key concept behind the integrated circuit.

Noyce's chip solved many practical problems that Kilby's had not. Noyce's chip, made at Fairchild Semiconductor , was made of silicon , whereas Kilby's chip was made of germanium. Philo Farnsworth developed the Farnsworth—Hirsch Fusor , or simply fusor, an apparatus designed by Farnsworth to create nuclear fusion.

Unlike most controlled fusion systems, which slowly heat a magnetically confined plasma , the fusor injects high temperature ions directly into a reaction chamber, thereby avoiding a considerable amount of complexity. When the Farnsworth-Hirsch Fusor was first introduced to the fusion research world in the late s, the Fusor was the first device that could clearly demonstrate it was producing fusion reactions at all. Hopes at the time were high that it could be quickly developed into a practical power source. However, as with other fusion experiments, development into a power source has proven difficult.

Nevertheless, the fusor has since become a practical neutron source and is produced commercially for this role. The mirror image of an electromagnet produces a field with the opposite polarity. Thus the north and south poles of a magnet have the same symmetry as left and right. Prior to , it was believed that this symmetry was perfect, and that a technician would be unable to distinguish the north and south poles of a magnet except by reference to left and right.

In that year, T. Lee and C. Yang predicted the nonconservation of parity in the weak interaction. To the surprise of many physicists, in C.

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Wu and collaborators at the U. National Bureau of Standards demonstrated that under suitable conditions for polarization of nuclei, the beta decay of cobalt preferentially releases electrons toward the south pole of an external magnetic field, and a somewhat higher number of gamma rays toward the north pole. As a result, the experimental apparatus does not behave comparably with its mirror image. The first step towards the Standard Model was Sheldon Glashow 's discovery, in , of a way to combine the electromagnetic and weak interactions. The Higgs mechanism is believed to give rise to the masses of all the elementary particles in the Standard Model. This includes the masses of the W and Z bosons , and the masses of the fermions - i. After the neutral weak currents caused by Z boson exchange were discovered at CERN in , [] [] [] [] the electroweak theory became widely accepted and Glashow, Salam, and Weinberg shared the Nobel Prize in Physics for discovering it.

The W and Z bosons were discovered experimentally in , and their masses were found to be as the Standard Model predicted. The theory of the strong interaction , to which many contributed, acquired its modern form around —74, when experiments confirmed that the hadrons were composed of fractionally charged quarks. With the establishment of quantum chromodynamics in the s finalized a set of fundamental and exchange particles, which allowed for the establishment of a " standard model " based on the mathematics of gauge invariance , which successfully described all forces except for gravity, and which remains generally accepted within the domain to which it is designed to be applied.

The formulation of the unification of the electromagnetic and weak interactions in the standard model is due to Abdus Salam , Steven Weinberg and, subsequently, Sheldon Glashow. After the discovery, made at CERN , of the existence of neutral weak currents , [] [] [] [] mediated by the Z boson foreseen in the standard model, the physicists Salam, Glashow and Weinberg received the Nobel Prize in Physics for their electroweak theory. Because of its success in explaining a wide variety of experimental results.

There are a range of emerging energy technologies. Also, the nanowire battery , a lithium-ion battery, was invented by a team led by Dr. Yi Cui in Reflecting the fundamental importance and applicability of Magnetic resonance imaging [] in medicine, Paul Lauterbur of the University of Illinois at Urbana—Champaign and Sir Peter Mansfield of the University of Nottingham were awarded the Nobel Prize in Physiology or Medicine for their "discoveries concerning magnetic resonance imaging". The Nobel citation acknowledged Lauterbur's insight of using magnetic field gradients to determine spatial localization , a discovery that allowed rapid acquisition of 2D images.

Wireless electricity is a form of wireless energy transfer , [] the ability to provide electrical energy to remote objects without wires. Its aim is to reduce the dependence on batteries. Further applications for this technology include transmission of information —it would not interfere with radio waves and thus could be used as a cheap and efficient communication device without requiring a license or a government permit.

A Grand Unified Theory GUT is a model in particle physics in which, at high energy, the electromagnetic force is merged with the other two gauge interactions of the Standard Model , the weak and strong nuclear forces. Many candidates have been proposed, but none is directly supported by experimental evidence. GUTs are often seen as intermediate steps towards a " Theory of Everything " TOE , a putative theory of theoretical physics that fully explains and links together all known physical phenomena, and, ideally, has predictive power for the outcome of any experiment that could be carried out in principle.

No such theory has yet been accepted by the physics community. The magnetic monopole [] in the quantum theory of magnetic charge started with a paper by the physicist Paul A. Dirac in In some theoretical models , magnetic monopoles are unlikely to be observed, because they are too massive to be created in particle accelerators , and also too rare in the Universe to enter a particle detector with much probability.

After more than twenty years of intensive research, the origin of high-temperature superconductivity is still not clear, but it seems that instead of electron-phonon attraction mechanisms , as in conventional superconductivity, one is dealing with genuine electronic mechanisms e. From Wikipedia, the free encyclopedia. For a chronological guide to this subject, see Timeline of electromagnetic theory. This article relies too much on references to primary sources. Please improve this by adding secondary or tertiary sources. October Learn how and when to remove this template message.

Electrical network. Covariant formulation. Electromagnetic tensor stress—energy tensor. Main article: electrostatic machine. Main article: Second Industrial Revolution. Main articles: History of special relativity and Lorentz ether theory. Main article: Annus Mirabilis papers. Main article: wireless energy transfer. Further information: WiTricity. Main article: Grand Unified Theory. Main article: Open problems in physics. Page Electricity in the service of man: a popular and practical treatise on the applications of electricity in modern life.

A treatise on electromagnetic phenomena, and on the compass and its deviations aboard ship. Mathematical, theoretical, and practical. New York: J. See, for example, "Magnet". Language Hat blog. Retrieved 22 March A history of the theories of aether and electricity from the age of Descartes to the close of the 19th century. Dublin University Press series.

London: Longmans, Green and Co. Magnet Academy. National High Magnetic Field Laboratory. Retrieved 21 April X, pp. New York: Encyclopedia Americana Corp. Murray,