Lecture Note
University
Massachusetts Institute of TechnologyCourse
Health Sciences and Technology (HST)Pages
2
Academic year
2023
gloriarundle
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Modern Physics Modern physics is the development of physics in the 20th century to the present which ismarked by the emergence of many revolutionary new theories and concepts. Some examplesof modern physics theories are: 1. The Theory of RelativityThe theory of relativity was coined by Albert Einstein in 1905 which changed the concept ofspace and time to no longer being absolute. There are 2 types of relativity theory:- Special Relativity: deals with the uniformity of the speed of light across all inertialreferences. Consequently time and length contract at a high rate.- General Relativity: gravity is understood as the bending of space and time. 2. Quantum MechanicsThis theory explains the wave-particle properties of matter and electromagnetic radiation aswell as the concepts of superposition, uncertainty, and quantum disaggregation. Quantummechanics gave rise to particle physics and condensed matter physics. 3. Particle PhysicsThrough particle accelerators, various new subatomic particles were discovered that formedthe standard model of particle physics. Examples of basic element particles of matter arequarks and leptons. 4. Physical CosmologyThe development of the Big Bang theory has provided new understanding of the origin of theuniverse from the singularity point explosion 13.8 billion years ago to continuous expansion. 5. Quantum Field TheoryThe theory of interactions between elementary element particles through the exchange offorce field particles, such as photons for electromagnetic interactions. Quantum field theoryunites quantum mechanics with special relativity. Modern physics has evolved rapidly in the 20-21 centuries thanks to the support ofcutting-edge research technologies such as particle accelerators and sophisticated detectorsand super-fast computing. Modern physics provides a deep understanding of the universe. Here are some examples of the application of modern physics in technology and everydaylife: 1. Laser TechnologyLasers used in material processing, fiber optic communications, and medical surgery arebased on the principle of light-stimulated emission, which is a quantum concept in modernphysics.
2. MRIMRI utilizes a magnetic field and radio waves to produce medical images of the human body.It is based on the behavior of the nuclear spin of the hydrogen atom in a magnetic field whichis a concept of quantum mechanics. 3. MicrochipThe microchips and transistors inside work based on the flow and behavior of electrons in thesemiconductor material. It is studied in particle physics and quantum mechanics. 4. RadioisotopesRadioisotopes such as gamma radiation, X-rays, and radioactivity are used in nuclearmedicine for diagnostics and therapy. Radioactivity is a core physics concept that includesmodern physics. 5. Big BangThis theory of the origin of the universe from the eruption of a singularity point is based onEinstein's general relativity and astronomical observations of the cosmic microwavebackground. 6. GPS SatellitesGPS satellites use relativistic corrections for more accurate positioning taking into accountthe effect of time dilation due to the speed of the satellite. Based on the special theory ofrelativity. 7. Particle PhysicsResearch into the physics of fundamental particles of matter at the CERN and Fermilabaccelerators is based on predictions of the standard model of particle physics within theframework of quantum field theory.
Science Lesson About Modern Physics
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