Electromagnetism.docx

EE-371

ASSIGNMENT#1 NAME:

MUHAMMAD USMAN

REG NO:

2016372

SECTION:

C

FACULTY:

EEP

ELECTROMAGNETIC THEORY: Electromagnetic Theory covers the basic principles of electromagnetism, experimental basis, electrostatics, magnetic fields of steady currents, motional e.m.f and electromagnetic induction, Maxwell's equations, propagation and radiation of electromagnetic waves, electric and magnetic properties of matter, and conservation laws. It uses appropriate mathematics but whose emphasis is on physical phenomena and principles. Electromagnetic phenomena are defined in terms of the electromagnetic force, sometimes called the Lorentz force, which includes both electricity and magnetism as different manifestations of the same phenomenon. The electromagnetic force plays a major role in determining the internal properties of most objects encountered in daily life. Ordinary matter takes its form as a result of intermolecular forces between individual atoms and molecules in matter, and is a manifestation of the electromagnetic force. Electrons are bound by the electromagnetic force to atomic nuclei, and their orbital shapes and their influence on nearby atoms with their electrons is described by quantum mechanics. The electromagnetic force governs all chemical processes, which arise from interactions between the electrons of neighboring atoms. APPLICATIONS: Electromagnetism has numerous applications in today’s world of science and physics. 

The very basic application of electromagnetism is in the use of motors. The motor has a switch that continuously switches the polarity of the outside of the motor. An electromagnet does the same thing. We can change the direction by simply reversing the current. The inside of the motor has an electromagnet, but the current is controlled in such a way that the outside magnet repels it.

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One of the most common uses of the properties of electromagnetism is in common speakers. In a speaker, there are a few main parts including a cone, a voice coil, and a permanent magnet. The ends of the voice coil are connected to the back of a panel receiver or stereo and the receiver sends a signal through the voice coil which

interacts with the magnetic field of the magnet which produces an alternating force that pushes and pulls on the cone. This pushing and pulling create sound waves. 

Television screens and computer monitors use solenoids to produce images by exerting magnetic forces on moving electrons also. In a television, there is an electron gun that fires a narrow beam of electrons at the screen of a tube.

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Another very useful application of electromagnetism is the “CAT scan machine.” This machine is usually used in hospitals to diagnose a disease. As we know that current is present in our body and the stronger the current, the strong is the magnetic field. This scanning technology is able to pick up the magnetic fields, and it can be easily identified where there is a great amount of electrical activity inside the body.

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The work of the human brain is based on electromagnetism. Electrical impulses cause the operations of the brain and it has some magnetic field. When two magnetic fields cross each other inside the brain, interference occurs which is not healthy for the brain. Electric fans, blowers and other cooling systems use electric motors. These motors work on the principle of electromagnetic induction which is the branch of electromagnetism. In any electrical appliance, electric motor is moved by the magnetic field produced by the electric current according to the Lorenz force principle. These motors are vary in size, rating and cost based on the application.

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Kitchen appliances like induction cookers, microwave ovens, electric mixers and grinders, bread toasters, etc. use the electromagnetism for their operation. Alarming systems use electrical bells which works based on electromagnetic principle. In these bells, the sound is produced by electromagnetic coils which move the striker against the bell. As long as the coil is energized, iron striker gets attracted by it, hence it strikes the bell. The electromagnets will be demagnetized when the striker get contact with bell and by the spring tension striker comes back to its original position and again electrical contact will be made once again. This process repeats until the switch gets opened. Various sensors and actuating devices are works based on electromagnetism. Electromagnetic sensors include Hall-effect sensors, magneto resistive sensors, fluxgate sensors, etc. These sensors convert the physical quantity such as flow, pressure, level, proximity, etc. into an electrical signal.

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Actuators are the final control elements which drives the load at specific conditions. These actuator devices include solenoid valves, relays, motors, etc. and all these works on the principle of electromagnetism.

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This is the modern technology of transportation systems that use the concept of electromagnetism. These are called as high speed trains which use powerful electromagnets to develop the speed. These trains will float over a guide way using the basic principles of magnets such as electromagnetic suspension (EMS) and electrodynamic suspension (EDS). In EMS, electromagnets employed on the train body are attracted to the iron rails.

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It is the process of transmitting information from a source to a receiver. This transmission of energy over long distances is carried out through electromagnetic waves at high frequencies. These waves are also called as microwaves or high frequency radio waves. Suppose in case of mobile phones, sound energy is converted into electromagnetic energy. By using radio transmitters, this electromagnetic energy is transferred to the receiver. At the receiver these electromagnetic waves are again transformed back into sound.

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Relays are used as safety devices. A large current circuit can be switched on by a small current circuit. When the small current in the input circuit is switched on, the electromagnet becomes magnetic and attracts the iron armature. The armature rotates towards the electromagnet, pushing the contacts together.

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The data in eBook gadgets and phones are stored in the electromagnetic format in the form of bytes and bits. The computer hardware is also having a magnetic tape which works on the principle of electromagnetism. Even in the olden days’ electromagnets had a huge role in the data storage of VCP and VCR.

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Without electromagnets, the mobiles and the telephones we use to make phone calls over long distance could not have taken shape. The electromagnetic pulses and the interaction of the signals make the mobiles and telephones very handy.

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An AC generator also known as an electric generator is a device which converts mechanical energy into electrical energy. The working of a dynamo is based on the theory of electromagnetic induction. When an armature coil is rotated in a magnetic field, the number of magnetic lines passing through the coil change due to which electricity is produced.

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A transformer is a device using which the amplitude of an alternating emf can be increased or decreased. A transformer works on the principle of electromagnetic

induction and makes use of two coils. A change in the magnetic field lines due to varying current in one coil (primary coil) produces an induced varying current of same frequency in the other coil (secondary coil). 

Electro-magnetic energy often is used to assess or aid in the diagnostic process when used in electromyography, biofeedback, electroencephalography, electroradiography, and in imaging tests such as magnetic resonance, positron emission tomography, computed tomography (CT), ultrasound, and radiography applications.

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Electromagnetic radiation is the foundation for working of radar which in turn is used for guiding and remote sensing the study of our planet Earth.