Electromagnetic Waves PDF

ELECTROMAGNETIC WAVES RELATIONSHIP OF FREQUENCY AND ENERGY: THEY ARE DIRECTLY PROPORTIONAL  How does electromagnetic waves are formed? Electromagnetic waves are formed when an electric field comes in contact with a magnetic field. They are hence known as 'electromagneti...

ELECTROMAGNETIC WAVES RELATIONSHIP OF FREQUENCY AND ENERGY: THEY ARE DIRECTLY PROPORTIONAL  How does electromagnetic waves are formed? Electromagnetic waves are formed when an electric field comes in contact with a magnetic field. They are hence known as 'electromagnetic' waves. WAVELENGTH – is also a basis to identify the energy of an em wave Together, they form electromagnetism. A moving electric charge generates a magnetic field. A magnetic field induces electric charge movement, producing an electric current. In an electromagnetic wave, the electric field and magnetic field are perpendicular to one another. ELECTROMAGNETIC WAVES Us e s Cha ract eris s tic RADIO WAVE  RADIO WAVE U s e s Cha rac teri s stic Radio waves are used for telecommunication such as television and radio. Radio waves are transmitted easily through air. They do not cause damage if absorbed by the human body, and they can be reflected to change their direction. These properties make them ideal for communications. MICROWAVE  MICROWAVE U s e s Cha rac teri s stic Microwaves are used for cooking food and for satellite communications. High frequency microwaves have frequencies which are easily absorbed by molecules in food. The internal energy of the molecules increases when they absorb microwaves, which causes heating. Microwaves pass easily through the atmosphere, so they can pass between stations on Earth and satellites in orbit. INFRARED VISIBLE LIGHT  VISIBLE LIGHT U s e s Cha rac teri s stic Visible light waves are the only wavelengths of the electromagnetic spectrum that humans can see. The different wavelengths of visible light are seen as the colors of the rainbow: red, orange, yellow, green, blue, indigo, and violet. We concentrate visible light to make lasers to use in everything from surgery, to CD players to laser pointers. Visible light waves also make our TV, computer and cell phone screens work. ULTRAVIOLET RAY  ULTRAVIOLET RAY U s e s Cha rac teri s stic Ultraviolet radiation can kill bacteria that are present in water - this sterilizes the water and makes it safe to drink. Ultraviolet radiation is also good for the skin as it helps to make vitamin D. However, too much exposure to UV can cause skin problems. X- RAY  X- RAY U s e s Cha rac teri s stic A number of electromagnetic waves are used for medical diagnosis purpose. For instance, X-Rays are used to get an image of tissues and bones, thereby allowing the medical examiner to locate broken bones or injured body tissues. MRI or magnetic resonance imaging also makes use of electromagnetic waves for the purpose of detecting and curing tumours and other disorders.  GAMMA- RAY U s e s Cha rac teri s stic Some of the electromagnetic radiations such as gamma rays have the ability to kill living cells. Due to this property of gamma rays, they are used in the medical industry in the treatment of cancer. When a cancerous cell or tissue is exposed to gamma rays, it gets eliminated, thereby curing the disease. GAMMA- RAY Light absorption is a process by which light is absorbed and converted into energy. BUT GREEN IS BEING REFLECTED BY LEAVES AND GRASSES FOR PHOTOSYNTHESIS  Reflection is when light bounces off an object. If the surface is smooth and shiny, like glass, water or polished metal, the light will reflect at the same angle as it hit the surface. This is called specular reflection.  The transmission of light occurs when light hits an object that is transparent or translucent and light can penetrate the material to travel all the way through. When light transmission happens, it can be scattered or refracted.  The refraction of light occurs because light travels with different speeds in different media. When a ray of light passes from one medium to another, its direction changes because of the change in its speed.  Dispersion of light is the splitting of white light into its constituent colors due to the refractive index of the surface and the wavelength of the light. 6. Medicine: Visible light is employed in various medical applications, such as light therapy for treating certain skin conditions and mood disorders, and surgical procedures that use lasers or other light-based technologies. 7. Agriculture: Visible light is critical for plant growth through the process of photosynthesis, which converts sunlight into chemical energy used by plants for growth and reproduction. 8. Art and Entertainment: Visible light is used in various forms of art and entertainment, including painting, theater, film, and light shows, to create visual experiences and convey emotions and ideas. 9. Spectroscopy: Visible light spectroscopy is used in fields such as chemistry, physics, and astronomy to analyze the properties of materials and celestial bodies, as well as to identify elements and compounds based on their absorption or emission spectra.