Electromagnetic Spectrum PDF Gulf Medical University

Electromagnetic spectrum December 25, 2024 www.gmu.ac.ae COLLEGE OF ALLIED HEALTH Learning Objectives At the end of the lecture, students will be able to: State the different constituents of electromagnetic spectrum in the order of incre...

Electromagnetic spectrum December 25, 2024 www.gmu.ac.ae COLLEGE OF ALLIED HEALTH Learning Objectives At the end of the lecture, students will be able to: State the different constituents of electromagnetic spectrum in the order of increasing or decreasing wavelength/frequency. List the application of each constituent of the electromagnetic spectrum. Electromagnetic Waves Electromagnetic waves are created as a result of vibrations between an electric field and a magnetic field. In other words, EM waves are composed of oscillating magnetic and electric fields. Electromagnetic waves are formed when an electric field comes in contact with a magnetic field. Electromagnetic Spectrum Electromagnetic Spectrum Laws governing radiation 6 Reflection 7 8  Infra-Red Radiation It is part of the electromagnetic spectrum covers the range from roughly 1 mm to 700-750 nm). Refraction 10 11 Absorption 12  “ultrasound at higher frequencies affects tissues that are more superficial, whereas at a lower frequency less energy is absorbed superficially and more is available to penetrate Denegar CR. Therapeutic Modalitiesinto for Athletic Injuries. Champaign, IL: Human Kinetics; 2000. pp. deeper tissues” 162–163. 13 14 15  Ultraviolet Rays Shorter wavelength and higher frequency than visible light Carry more energy than visible light Causes your skin to produce vitamin D (good for teeth and bones) Used in eye surgery-laser surgery Used to kill bacteria- Sterilization of surgical instrument and in water purifers Excessive Exposure: Use sun block to protect against (UV 17 18  Short Wave Diathermy Most commercial machines operate at a frequency of 27.12 MHz, a wavelength of approximately 11 meters High frequency electromagnetic waves to heat deep tissues.  Microwave Diathermy Microwaves are electromagnetic waves of a wavelength from 0.1 to 100 cm. They can be generated by a special generating lamp called a magnetron. Easily focused than the waves used in short wave diathermy, decreasing energy leaking and thus making heating more efficient and Radiotherapy It is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. At low doses, radiation is used in x-rays to see inside your body, as with x- rays of your teeth or broken bones. Gamma Rays Shorter wavelength and higher frequency than X- rays Carry the greatest amount of energy and penetrate the most. Used in radiation treatment to kill cancer cells. Can be very harmful if not used correctly.  Practice MCQ 1. Sound radiation waves that change direction when passing from one type of tissue to other is said to: A. Transmit B. Absorb C. Refract D. Reflect 2. Which among the listed law states that if superficial tissue does not absorb energy, it must be transmitted deeper A. Law of Grotthus B. Cosine law C. Inverse Square law. D. Arndt-Scultz principle 3. According to Cosine law, one of the option below is the appropriate angle of ray to the surface in order to minimize refraction and maximize absorption A. 0 degree B. 90 degree C. 180 degree D.45 degree