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Electromagnetics 11-ES 207 L- T-P : 3-1-0 Credits: 4 Bhanu Prakash Assoc. Professor EEE Department Session Learning Objectives: (points to be discussed) Need of “Electromagnetics (course)” Principle of generation Classification Sources of Electromagnetic waves Advantages & Disadvantages Applications Bhanu Prakash @ K L University Need of “Electromagnetics” Study ? Electromagnetic fields (EMF) are all around us. We need them to see, to listen to radio and watch television, to communicate using mobile phones, and to run motors, fans, relays etc. we generate them every time we turn on a light switch or use an electric appliance. Bhanu Prakash @ K L University Faraday's law of induction: (1830s) Explanation-1 Bhanu Prakash @ K L University Explanation-2 How to produce/ generate/ induce Electric Field ? Bhanu Prakash @ K L University Electric Fields: Electric fields arise from voltage (Current Carrying conductor) An electric field can be present even when a device is switched off. Field strength decreases with distance from the source. Most building materials shield electric fields to some extent. Bhanu Prakash @ K L University How to produce/ generate/ induce Magnetic Field ? Bhanu Prakash @ K L University Magnetic Fields: Magnetic fields arise from current flows. Magnetic fields exist as soon as a device is switched on and current flows. Field strength decreases with distance from the sources. Magnetic fields are not attenuated by most materials. Bhanu Prakash @ K L University Which of the following is Electric field or Magnetic field or both? Fig.-2 Fig.-1 Fig.-3 Bhanu Prakash @ K L University Fig.-4 Types of Electromagnetic Radiations • • • • • • • AM and FM radio waves (including TV signals) Cell phone communication links Microwaves Infrared radiation Light X-rays Gamma rays What distinguishes these from one another? Bhanu Prakash @ K L University i.e. Classification Type Frequency Range Extremely Low Frequency 3 Hz – 3 KHz Radio Waves 3 KHz – 300 MHz Microwaves 300 MHz – 300 GHz Infrared radiation Ultraviolet radiation X-rays 300 GHz – 300 300 THz – 300 THz – 30 PHz THz 30 PHz Bhanu Prakash @ K L University Gamma rays 30 PHz – 30 EHz Is there any insulation for Current? Is there any insulation for Field (Flux) ? Bhanu Prakash @ K L University Which is most liking place in your Home? Kitchen room Hall Bed room Bathroom Bhanu Prakash @ K L University Sources of Electromagnetic fields Frequency Range 3 Hz – 3 KHz 3 KHz – 300 MHz Type Common Sources Power lines, appliances, Extremely Low Frequency electronics AM/FM radio, television Radio Waves broadcasting, CB radios 300 MHz – 300 GHz Microwaves 300 GHz – 300 THz Infrared radiation 300 THz – 30 PHz Ultraviolet radiation 300 THz – 30 PHz 30 PHz – 30 EHz X-rays Gamma rays Cell phones, wireless internet, satellite broadcasting, microwave ovens, radar, medical imaging Lasers, alarm systems, motion detectors Fluorescent and incandescent lights X-ray medical imaging Nuclear material Bhanu Prakash @ K L University Sources of Electromagnetic fields Contd…… computers and related microwave ovens equipment computer screens (especially the older types), information networks electrical appliances (including TV's) electronic equipment Cell phones cell phone masts radio and TV transmitters microwave transmitters or ovens, house-wiring high and low voltage power lines cars, motor cycles, buses, trains, planes. high voltage transformers, transmission cables & Lines pylons. Bhanu Prakash @ K L University Bhanu Prakash @ K L University What are the sources of EM waves in this Lecture hall? Bhanu Prakash @ K L University Field distributions Electromagnetic fields inside a Motor Electromagnetic fields inside a desktop computer The H-field on the whole surface of an airplane Bhanu Prakash @ K L University Disadvantages Bhanu Prakash @ K L University Which is most liking place in your Home? Kitchen room Hall Bed room Bathroom Bhanu Prakash @ K L University Electromagnetic field radiation (EMF) is emanating from virtually every single electrical appliance, computer, electric wire, and especially high voltage lines (overhead and buried), which are carrying current. EMF is specifically causing cancer in children and in older adults and may be triggering countless other immune deficiency and psychological diseases and disorders in anyone in close proximity. Many scientists warn people not to live within 200 yards (190m) of high voltage power lines. Of 35 international research studies on electric field radiation, 33 established a conclusive link between brain tumors, leukemia, and other forms of cancer. Bhanu Prakash @ K L University The Bedroom Is Often the Most Dangerous Place In the Home Many researchers and scientists now feel that electromagnetic field radiation, both from within and without the bedroom, is the single biggest factor in poor sleep. And poor health. Look around your bedroom. Is there a clock radio on the nightstand near your pillow? A TV? A stereo? A cell phone below the pillow (bedmate)? A Laptop near to you/ your bed? Are there high voltage power lines with close to your residence? All or any of these electric sources can ruin your sleep and can substantially increase your risk of developing cancer and any number of diseases, both psychological and physical. Bhanu Prakash @ K L University While you sleep, your body relaxes and is unconscious. In this state of vulnerability, research indicates you are 100-150 times more open to the damage of electromagnetic radiation that when you are awake. Children are often up to 1,000 times more sensitive to these fields when they are asleep. (TV screen in your bedroom will radiate energy all night...even after it has been unplugged. It can take hours or even days for the built-up voltage in the television to dissipate. ) Do not leave any thing plugged in while you sleep, even if it is turned off. Outside high voltage power lines continually radiate EMF 24 hours a day. Bhanu Prakash @ K L University Biological Effects of Electromagnetic Radiation Protein Changes in Skin Excited Brain Cells DNA Damage Brain Cell Damage Aggressive Growth in Leukemia Cells Increased Blood Pressure Harmful Effects of ElectroMagnetic Radiation Salivary Gland Cancer Brain Tumour Lymphatic Cancer and Bone Marrow Cancer Miscarriage Asthma Bhanu Prakash @ K L University Bhanu Prakash @ K L University Size of the Substations 11KV/132KV 132KV/33KV 132KV/11KV 33KV/11KV Bhanu Prakash @ K L University Bhanu Prakash @ K L University Easy to generate, use, and applicable in many implements. Easy hand rules to understand flow direction, force, and polarity too. Can be used in incredibly small to very large situation (i.e. pacemakers or trains) Electromagnetic energy is clean. It is not polluting Bhanu Prakash @ K L University Applications: • • • • • • • • • • • • Motors and generators Transformers Relays Electric bells Loudspeakers Magnetic recording and data storage equipment: tape recorders, VCRs, hard disks Scientific instruments such as MRI machines and mass spectrometers Particle accelerators Magnetic locks Magnetic separation of material Industrial lifting magnets Electromagnetic suspension used for MAGLEV trains Bhanu Prakash @ K L University Applications: • • • • • • • • • • • Contd…. Radars Cooking (with microwaves) Medical Imaging (X rays) “Night Vision” (infrared) Astronomy (radio, wave, IR, visible, UV, gamma) Satellite Communication TV Communication Wireless Communication Mobile Communication Microwave Communication This theory is also used in analysis and designing of antenna, transmission lines and wave guides. All that we experience through our eyes is conveyed by electromagnetic radiation… Bhanu Prakash @ K L University Applications: (Medical) Contd…. • Magnetic resonance imaging used in diagnostic. In this case is used a static magnetic field (a few Tesla) with a radio frequency signal superimposed • Hyperthermia uses electromagnetic fields for the treatment of cancer by means of tissue heating; • Electric stimulation: the stimulation of the hippocampus by means of electric field can be used in some brain therapy like Parkinson or neurological diseases. • Pulsed electromagnetic fields can affect the osteoblaste proliferation for bone reparation and favorite the wound healing. Bhanu Prakash @ K L University Points discussed : (Summary) Bhanu Prakash @ K L University Doubts/Questions? Doubt is worst Enemy! If you still have enemies Send them to [email protected] Bhanu Prakash @ K L University