Page 1 :
Chapter 1, Physical World, , What is science ?, , The word science originates from the latin verb Scientia meaning, ‘to know’., , Science is a systematic attempt to understand natural phenomena in as, much detail and depth as possible, and use the knowledge so gained to, predict ,modify and control phenomena., , Scientific method, Scientific method involves the following steps, , 1) Systematic observations., , 2) Controlled experiments, , 3) Quantitative and qualitative reasoning, , 4) Mathematical modelling, , 5) Prediction and verification and falsification of theories., , What is Physics?, , Physics is the study of the basic laws of nature and their manifestation, in different natural phenomena, , * Physics is a basic discipline in the catagory of natural sciences, which, also includes other disciplines Chemistry and Biology., , * The word physics comes from a Greek word meaning nature ., , * The two principal thrusts in physics are unification and reduction, , Unification - In physics we attempt to explain diverse physical, phenomena in terms of few concepts and laws. This is unification, , Redcction - To derive the properties of , more complex, system, from the properties and interactions of its constituent simpler, parts is called reductionism ., , Dowloaded from www.hssreporter.com
Page 2 :
Scope and Excitement of Physics, , Basically, there are two domains of interest : macroscopic and, microscopic., , The macroscopic domain includes phenomena at the laboratory,, terrestrialand astronomical scales. Classical physics deals with, macroscopic domain., , The microscopic domain includes atomic, molecular and nuclear, phenomena. Classical physics is inadequate to handle this domain., Modern Physics uses Quantum Theory to explain microscopic, domain., , Classical Physics (macroscopic), , Mechanics Electrodynamics Optics Thermodynamics., , Mechanics has its foundation on Newton’s laws of motion and, the law of gravitation.It deals with motion of particles,rigid and, deformable bodies,propulsion of rocket,propagation of water waves, or sound waves, , Electrodynamics deals with electric and magnetic phenomena, associated with charged and magnetic bodies., , Optics deals with the phenomena involving light., Thermodynamics deals with changes in internal energy,, , temperature, entropy, etc., of the system through external work, and transfer of heat., , Dowloaded from www.hssreporter.com
Page 3 :
Fundamental Forces in Nature, There are four fundamental forces in nature, , , , , , , , , , , , , , , , , , , , , , , , , , Forces _| Gravitational Force Weak NuclearForce | ElectromagneticForce | Strong Nuclear, Force, What? |Itistheforceofmutual — | The weaknuclear Electromagneticforceis | The strong nuclear, attraction between any two | forceappearsonlyin | the force between force binds protons, objects by virtue oftheir | certainnuclear charged particles, and neutronsina, masses processes such asthe nucleus,, B-decay ofa nucleus,, Operates | All objects in nature Some elementary Charged particles Nucleons, heavier, among particles, particularly elementary particles, electron and neutrino, Range | Long range force; Infinite | Very short, Sub- Long range Short, nuclear size, nuclear size force;Infinite (~10"m), (~10-'m), Nature | Always attractive Not attractive or Similar charges repel and | Always attractive, repulsive opposite charges attract. | Force between n-n,, P-p,n-pare same, ‘ Stronger than gravitational | Stronger than gravitational and, Weakestforcein |i aterttan | weakradearfore butwerker | Strongest force, nature electromagnetic force than strong nuclearforce innature, Relative 10°? 10°" 107 1, strength {, , , , Conservation Laws in Physics, , The physical quantities that remain unchanged in a process, are called conserved quantities. Some of the general conservation, laws in nature include the laws of conservation of mass, energy,, linear momentum, angular momentum, charge, parity,etc. Some, conservation laws are true for one fundamental force but not, for the other. Conservation laws have a deep connection with, symmetries of nature. Symmetries of space and time, and other, types of symmetries play a central role in modern theories of, fundamental forces in nature., , Dowloaded from www.hssreporter.com
Page 4 :
Technology _ Scientific principle(s), , Steam engine Laws of thermodynamics, , Radio and Television Generation, propagation and detection of, electromagnetic waves, , Nuclear reactor Controlled nuclear fission, , Computers Digital logic, , Rocketpropulsion | Newton's laws ofmotion, , Electricgenerator | Faraday’s laws of electromagnetic induction, , Aeroplane Bernoulli's principle in fluid dynamics, , Optical fibres Total internal reflection of light, , Electron microscope | Wave nature of electrons, , Photocell Photoelectric effect, , Sonar Reflection of ultrasonic waves, , Lasers Light amplification by stimulated emission of radiation, , , , , , Dowloaded from www.hssreporter.com
Page 5 :
Archimedes, , Galileo Galilei, , Isaac Newton, Christiaan Huygens, James Clerk Maxwell, Heinrich Rudolf Hertz, J.C. Bose, , WK. Roentgen, , ].). Thomson, , Marie Sklodowska Curie, , Albert Einstein, Ernest Rutherford, Niels Bohr, , C.V. Raman, , Louis Victor de Borglie, M.N.Saha, , S.N. Bose, , James Chadwick, , Principle of buoyancy; Principle of the lever Greece, Lawofinertia Italy, Universal law of gravitation; Lawsof motion; Reflecting telescope U.K., Wavetheory of light Holland, Electromagnetictheory; Light-an electromagneticwave UK., Generation of electromagnetic waves Germany, Ultrashortradio waves India, X-rays Germany, Electron UK, Discovery of radium and polonium; Studies on natural Poland, radioactivity, Explanation of photoelectric effect; Theory of relativity Germany, Nuclear model of atom New Zealand, Quantum model of hydrogenatom Denmark, Inelastic scattering of light by molecules India, Wave nature of matter France, Thermal ionisation India, Quantum statistics India, Neutron UK., , Seema Elizabeth, , Dowloaded from www.hssreporter.com, , MARM Govt HSS Santhipuram
