DISCOVERIES . pptx By Sai S . Darawade

Discoveries made by renowned scientists

1. THE DISCOVERIES By - Sai S. Darawade

2. ARCHIMEDES This Photo by Unknown Author is licensed under CC BY-SA What is Buoyancy? A body at rest in a fluid is acted upon by a force pushing upward called the buoyant force, which is equal to the weight of the fluid that the body displaces. If the body is completely submerged, the volume of fluid displaced is equal to the volume of the body . Principle of Lever? It has been found by experiment that two equal forces acting in opposite directions, i.e., clockwise and counterclockwise, and applied to a uniform lever at equal distances from the fulcrum counteract each other and establish a state of equilibrium, or balance, in the lever.

3. Galileo Galilei Law of Inertia? I f a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force . Sample Footer Text 2/8/20XX 3 This Photo by Unknown Author is licensed under CC BY-SA

4. CHRISTIAAN HUYGENS Wave Theory of Light? According to wave theory, light from a source is propagated in the form of longitudinal waves with uniform velocity in a homogeneous medium. (Later it was proved that the light waves are transverse waves). These waves emitted by the source move in a straight in a homogeneous medium. Sample Footer Text 2/8/20XX 4 This Photo by Unknown Author is licensed under CC BY-SA-NC

5. IsaAc Newton Law of Gravitation? Newton’s Law of Universal Gravitation states that every particle attracts every other particle in the universe with force directly proportional to the product of the masses and inversely proportional to the square of the distance between them. Sample Footer Text 2/8/20XX 5 Laws of Motion? 1 st Law- law states that a body at rest or uniform motion will continue to be at rest or uniform motion until and unless a net external force acts on it. 2 nd Law- 2nd law states that the acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the object’s mass. (F=ma) 3 rd Law-   3rd law states that there is an equal and opposite reaction for every action.

6. MICHAEL FARADAY This Photo by Unknown Author is licensed under CC BY-SA Law of Electromagnetic Induction ? Faraday’s Laws of Electromagnetic Induction consists of two laws. The first law describes the induction of emf in a conductor and the second law quantifies the emf produced in the conductor. First Law – Whenever a conductor is placed in a varying magnetic field, an electromotive force is induced. If the conductor circuit is closed, a current is induced, which is called induced current. Second Law- The induced emf in a coil is equal to the rate of change of flux linkage.

7. JAMES CLEARK MAXWELL Electromagnetic Theory? Electromagnetic theory based on Maxwell's equations establishes the basic principle of electrical and electronic circuits over the entire frequency spectrum from DC to optics. It is the basis of Kirchhoff's current and voltage laws for low-frequency circuits and Snell's law of reflection in optics. Sample Footer Text 2/8/20XX 7 This Photo by Unknown Author is licensed under CC BY-NC-ND

8. HEINRICH RUDOLF HERTZ Sample Footer Text 2/8/20XX 8 This Photo by Unknown Author is licensed under CC BY-NC-ND Generation of Electromagnetic Waves? Electromagnetic waves are produced whenever electric charges are accelerated. This makes it possible to produce electromagnetic waves by letting an alternating current flow through a wire, an antenna. The frequency of the waves created in this way equals the frequency of the alternating current.

9. J.C. BOSE Ultra shot radio waves Shortwave radio is radio transmission using shortwave (SW) radio frequencies. The range always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (100 to 10 metres ); above the medium frequency band (MF), to the bottom of the VHF band 9

10. W.K.ROENTGEN Sample Footer Text 2/8/20XX 10 This Photo by Unknown Author is licensed under CC BY-SA X-RAYS X-rays are a type of radiation called electromagnetic waves. X-ray imaging creates pictures of the inside of your body. The images show the parts of your body in different shades of black and white. This is because different tissues absorb different amounts of radiation

11. J.J. THOMSON ELECTRON- Sample Footer Text 2/8/20XX 11 This Photo by Unknown Author is licensed under CC BY-SA It is a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.

12. MARIE CURIE Discoveries on radium and polonium Studies on Natural Redioactivity Sample Footer Text 2/8/20XX 12 This Photo by Unknown Author is licensed under CC BY-SA-NC

13. ALBERT EINSTEIN This Photo by Unknown Author is licensed under CC BY Photo Electric Effect It is a phenomina in which the electron are released from any metallic surface when it absorbs electro magnetic radiations Theory of Relativity I n his theory of special relativity, determined that the laws of physics are the same for all non-accelerating observers, and he showed that the  speed of light  within a vacuum is the same no matter the speed at which an observer travels, according to  Wired .  As a result, he found that space and time were interwoven into a single continuum known as space-time. And events that occur at the same time for one observer could  occur at different times  for another.

14. VICTOR FRANCIS HESS Cosmic Radiation Radiation from space  is called cosmic radiation, which is constantly hitting the Earth. Our solar system's Sun and other stars in the galaxy emit a constant stream of cosmic radiation. In the United States, a person gets about 5% of their annual radiation exposure from cosmic radiation Sample Footer Text 2/8/20XX 14

15. R.K. MILLIKAN Sample Footer Text 2/8/20XX 15 Measurement Of Electronic Charge This Photo by Unknown Author is licensed under CC BY-SA The SI derived unit of quantity of electric charge is the  coulomb  (symbol: C). The coulomb is defined as the quantity of charge that passes through the cross section of an electrical conductor carrying one ampere for one second.

16. ERNEST RUTHERFORD This Photo by Unknown Author is licensed under CC BY-NC-ND Nuclear Model Of Atom In the nuclear atom, the protons and neutrons, which comprise nearly all of the mass of the atom, are located in the nucleus at the center of the atom. The electrons are distributed around the nucleus and occupy most of the volume of the atom.

17. NIELS BOHR Quantam Model Of Hydrogen Sample Footer Text 2/8/20XX 17 This Photo by Unknown Author is licensed under CC BY Bohr’s model of the hydrogen atom is based on three postulates: (1) an electron moves around the nucleus in a circular orbit (2) an electron’s angular momentum in the orbit is quantized, and (3) the change in an electron’s energy as it makes a quantum jump from one orbit to another is always accompanied by the emission or absorption of a photon. Bohr’s model is semi-classical because it combines the classical concept of electron orbit with the new concept of quantization.

18. C.V. RAMAN 18 Inelastic Scattering Of Light By Molecules Inelastic scattering occurs  when there is an interaction that causes loss of energy of the incident primary electron . Inelastically scattered electrons have a longer wavelength

19. LOUIS VICTOR DE BORGLIE Wave Nature Of Matter Sample Footer Text 2/8/20XX 19 This Photo by Unknown Author is licensed under CC BY-SA The significance of the de Broglie relationship is that it proves mathematically that matter can behave as a wave. de Broglie equation says that every moving particle – microscopic or macroscopic –has its own wavelength.  For macroscopic objects, the wave nature of matter is observable .

20. M.N. SAHA Thermal Iionisation Sample Footer Text 2/8/20XX 20 Thermal ionization, also known as surface ionization or contact ionization, is  a physical process whereby the atoms are desorbed from a hot surface, and in the process are ionized . Thermal ionization is used to make simple ion sources, for mass spectrometry and for generating ion beams.

21. S.N. BOSE Higs Bosons 2/8/20XX 21 The Higgs boson is  the fundamental particle associated with the Higgs field, a field that gives mass to other fundamental particles such as electrons and quarks . A particle's mass determines how much it resists changing its speed or position when it encounters a force.

22. WOLFGANG PAULI Exclusion Principle Sample Footer Text 2/8/20XX 22 Pauli's Exclusion Principle states that  no two electrons in the same atom can have identical values for all four of their quantum numbers . In other words, (1) no more than two electrons can occupy the same orbital and (2) two electrons in the same orbital must have opposite spins 

23. ENRICO FERMI Controlled nuclear fission 2/8/20XX 23 This Photo by Unknown Author is licensed under CC BY-SA-NC          To maintain a sustained controlled nuclear reaction, for every 2 or 3 neutrons released, only one must be allowed to strike another uranium nucleus . If this ratio is less than one then the reaction will die out; if it is greater than one it will grow uncontrolled (an atomic explosion).

24. WERNER HEISENBERG Quantam Mechanics; Uncertainty principle Sample Footer Text 2/8/20XX 24 This Photo by Unknown Author is licensed under CC BY-NC-ND Formulated by the German physicist and Nobel laureate Werner Heisenberg in 1927, the uncertainty principle states that we cannot know both the position and speed of a particle, such as a photon or electron, with perfect accuracy; the more we nail down the particle's position, the less we know about its speed and vice versa.

25. PAUL DIRAC This Photo by Unknown Author is licensed under CC BY-SA-NC Relativistic Theory of electron In 1928,  Paul Dirac formulated a Hamiltonian that can describe electrons moving close to the speed of light , thus successfully combining quantum theory with special relativity. Another triumph of Dirac's theory is that it accurately predicts the magnetic moment of the electron.

26. EDWIN HUBBLE 2/8/20XX Sample Footer Text 26 This Photo by Unknown Author is licensed under CC BY Expanding Universe By studying the light emitted from various galaxies, Hubble discovered that the light appeared displaced toward the red end of the spectrum. It became apparent that our universe was ceaselessly expanding outward, and all galaxies housed within it were moving away from one another.

27. ERNST ORLANDO LAWRENCE Cyclotrone JAMES CHADWICK Neutron HIDKI YUKAWA Theory of nuclear Forces Sample Footer Text 2/8/20XX 27 A cyclotron is  a type of particle accelerator which repeatedly propels a beam of charged particles (protons) in a circular path . Medical radioisotopes are made from non-radioactive materials (stable isotopes) which are bombarded by these protons. Neutrons, along with protons, are  subatomic particles found inside the nucleus of every atom . The only exception is hydrogen, where the nucleus contains only a single proton. Neutrons have a neutral electric charge (neither negative nor positive) and have slightly more mass than positively charged protons. Nuclear forces (also known as nuclear interactions) are  the forces that act between two or more nucleons . They bind protons and neutrons ( together called nucleons) into the atomic nuclei. The nuclear force is a short-range force and causes the stability of the nucleus

28. HOMI JEHANGIR BHABHA Cascade process of cosmic radiation Sample Footer Text 2/8/20XX 28 The initial interactions in the upper atmosphere produce large numbers of charged and neutral pions . The charged pions decay into muons and muon neutrinos whereas the uncharged pions decay into pairs of high energy photons which become the starting points of large cascades of electrons, positrons and gamma rays.

29. LEV DAVIDOVICH LANDAU Theory of condensed matter Sample Footer Text 2/8/20XX 29 Condensed matter physics is the study of the macroscopic and mesoscopic properties of matter. Condensed matter theory  seeks to use the well-established laws of microscopic physics to predict the collective and structural properties of large numbers of electrons, atoms or molecules .

30. S. CHANDRASEKHAR Chandrasekhar limit, structure and evolution of stars Sample Footer Text 2/8/20XX 30 Condensed matter physics is the study of the macroscopic and mesoscopic properties of matter. Condensed matter theory seeks to use the well-established laws of microscopic physics to predict the collective and structural properties of large numbers of electrons, atoms or molecules.

31. JOHN BARDEEN Transistors Theory of super conductivity Sample Footer Text 2/8/20XX 31 The BCS theory of superconductivity (Bardeen-Cooper-Schrieffer) was  advanced in 1957 and became the basis for all later theoretical works on the subject . Bardeen later served as a professor of electrical engineering and physics at the University of Illinois, Urbana-Champaign between 1951 and 1975.

32. C.H. TOWENS Maser; Laser A maser is a device that produces  coherent   electromagnetic waves  ( microwaves ), through amplification by  stimulated emission . The term is an acronym for microwave amplification by stimulated emission of radiation. The first maser was built by  Charles H. Townes ,  James P. Gordon , and  Herbert J. Zeiger  at  Columbia University  in 1953. Townes,  Nikolay Basov  and  Alexander Prokhorov  were awarded the 1964  Nobel Prize in Physics  for theoretical work leading to the maser. Masers are also used as the timekeeping device in  atomic clocks , and as extremely low-noise  microwave  amplifiers in  radio telescopes  and deep-space  spacecraft communication  ground stations.

33. ABDUS SALAM Unification of weak and electromagnetic interations Sample Footer Text 2/8/20XX 33 Mathematically,  electromagnetism is unified with the weak interactions as a Yang–Mills field with an SU(2) × U(1) gauge group , which describes the formal operations that can be applied to the electroweak gauge fields without changing the dynamics of the system.

34. https://www.youtube.com/watch?v=2JsKwyRFiYY THANK YOU