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Electromagnetic Waves

Electromagnetic Waves

Text Box: Physics Physics, major science, dealing with the fundamental constituents of the universe, the forces they exert on one another, and the results produced by these forces. Sometimes in modern physics a more sophisticated approach is taken that incorporates elements of the three areas listed above; it relates to the laws of symmetry and conservation, such as those pertaining to energy, momentum, charge, and parity. The two domains of interest in physics are: Macroscopic Microscopic Classical Physics The macroscopic domain includes the study of phenomena involving objects of finite size on terrestrial scale and even on astronomical scale. This make up classical physics includes subjects like mechanics, thermodynamics, Electrodynamics and optics etc. Quantum Physics (Modern Physics) The Microscopic domain includes the study of phenomena involving molecules, atoms, nuclei electrons and other elementary particles. This makes up Quantum Physics or Modern Physics. Scope of physics It covers a very wide range of magnitudes of physical quantities like length, mass, time, energies. Excitement of physics. Physics deals with vastly diverse disciplines such as mechanics, heat , light , electricity, modern physics, etc. the study of ‘mechanics’ helps us to know the forces involved in the flight of a bird, in the walk of a man, in the collision between two microscopic or macroscopic bodies, in the freely falling bodies and so on. The study of “Heat” helps us to know the raise and fall of temperature, the working of heat engines, the conductivity of heat and so on. The study of “Light” gives us an insight in to the properties of lenses, mirrors etc. electricity helps to understand the basic principles involved in generators and motors. The exiting discipline of Modern Physics takes us in to the highly microscopic world of atoms and electrons. What makes it possible to understand such diverse physical phenomena? The first and foremost task is to describe qualitatively and not just quantitatively all that we observe. Certain laws emerge out of quantitative description. These laws help us to understand our observations and to comprehend cause effect relationships. The second task is to distinguish the “less important “from the “important” features of a problem. If we can do so effectively, then a given complex problem may appear to be pretty simple. Some Examples of excitement of Physics The discovery of sped of light 10-22 s to 108 s. The range of masses 10-39 kg to 1055 kg. Scale of galaxies or even the entire universe were extent is of order of 1026 m. Photon Its is a charged particle, It is responsible for gravitation. Physics is related to society Mathematics Physics in field of Mathematics is used in various ways for measuring different things and it is used in calculations, derivatives and formulas. Biology Physics in field of Biology is used in X-Rays of different body parts in medical. It is also used in diagnostic centers. Chemistry Physics in field of Chemistry is related that the chemicals are used as a fluid in hydraulic brakes. Astronomy Physics in field of Astronomy is closely related that many space satellites ate launched for many purposes. Technology Physics in field of technology is used for many more purpose like :- Light emission STD connection Lasers Automobiles House hold machenes Basic Forces Of Nature Gravitational Forces Electromagnetic Forces Strong Force Weak Force Gravitational Forces Universal law of gravitation F directly proportional to m1m2 (Product of mass of the body) F is inversely proportional to r2(square of the distance between them) F is directly proportional to m1m2/r2 F is equal to Gm1m2/r2 (where G is the gravitational constant) G = 6.67*10-11 Nm2Kg-2 (This was given by Henri Convendish) Characteristics of gravitational force 1. They are universal attractive forces. 2. They are the weakest forces in nature. 3. They operate over long distances. ( F α 1/r2) Universal Square Law It obeys Inverse square law. They are conservative in nature ( Non hanging) W=F.s cosө { Where ө is the angle between the Force vector (F) and Displacement vector (s) } 6. They act along the line joining the centers of two body. Graviton partial is responsible for gravitational force between two bodies. Electromagnetic Force Charge It is the fundamental particle which produce electric force a part from gravitational force. The forces exerted by one particle on the another is because of the electrical charges present in the particle is called electromagnetic force. Coulomb Force F directly proportional to q1q2 {Product of charges (q) of the two particles} F is inversely proportional to r2 (square of the distance between them) F is directly proportional to q1q2/r2 F is equal to Kq1q2/r2 Properties They are attractive or repulsive forces in nature. They are governed by coulomb's law. They obey inverse square law. Operate over a moderate distance. They depend on medium between the charges. They are conservative in nature. They are around 1032 times bigger than gravitation. The field particle responsible for electromagnetic force us photon. Strong Force {Strong Nuclear Force (Properties)} Strongest force in nature. Moson is field particle for nuclear force. Nuclear force independent of charge. It is of very short range (1015m). They don't obey inverse Square law . They are not conservative in nature. They are attractive type force. Weak Force (Weak Nuclear Force) It appears only in certain nuclear process such as β – decay at the nucleus. β – decay on’ 1H1 + -1eo + 8 (neutron) This electron and neutron interact through weak nuclear force. eo electron +1eo positron β- -1eo + 8 (bar) β+ +1eo + 8 The interaction is within elementary particle which is 10-13 times less than strong nuclear force. It is very short range force. Field particle responsible for weak nuclear force is Boson.

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