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Total Internal Reflection Physics
 
02:10
Check out us at:http://www.tutorvista.com/content/physics/physics-ii/light-refraction/total-internal-reflection.php Total Internal Reflection Let us consider a ray of light passing from glass to air, that is from a denser medium to a rarer medium. The figure shows that for a small angle of incidence, major part of the incident light is refracted and a small portion is reflected. The refracted ray bends away from the normal after the refraction. That is, the angle of refraction r is greater than the angle of incidence i. Now if we increase the angle of incidence, the angle of refraction also increases and for a certain angle of incidence (say ic), the refracted ray grazes over the surface of separation and the angle of refraction will be 90o. ic is referred to as the critical angle. If we further increase angle of incidence, the light ray instead of getting refracted bounces back into the same medium obeying the laws of reflection. This is known as total internal reflection. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
Views: 124311 TutorVista
Ruby Laser
 
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Check out us at:http://www.tutorvista.com/content/physics/physics-iv/communication-systems/ruby-laser.php Ruby Laser Ruby laser is a solid state laser. It consists of a pink ruby cylindrical rod whose ends are optically flat and parallel. one end of the rod is fully silvered and the other end is partially silvered. the rod is surrounded by a high intensity helical flash lamp filled with xenon gas which provides sufficient light to produce population inversion. Ruby is crystalline aluminium oxide(Al2O3) doped with 0.05% of chromium atoms.here some of the aluminium ions in the crystal are replaced by Chromium ions.the Al2O3 is known as host crystal and Cr atoms are called activator atoms. Here the chromium ions gives the transparent Al2O3 crystal pink or red color depending upon the concentration. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
Views: 133997 TutorVista
Davisson Germer Experiment
 
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Follow us at: https://plus.google.com/+tutorvista/ Check out us at:http://www.tutorvista.com/content/physics/physics-iv/radiation-and-matter/davison-and-germer-experiment.php Davisson Germer Experiment In the experimental set up Davisson and Germer there is a filament of tungsten coated with barium oxide, which on heating with the electric current from a battery emits large number of electrons. There is a hollow metallic cylinder with a hole along the axis. This hollow metal cylinder surrounds the filament and is kept at negative potential, so that the electrons emitted from filament may form a convergent beam of electrons. The hollow metallic cylinder acts as cathode. The other cylinder with a fine hole along its axis is kept at positive potential with respect to the cathode, acts as anode. The cathode and the anode form an electron gun, by which a fine beam of electrons can be obtained under different accelerating potentials applied between cathode and anode. There is a nickel crystal cut along the cubical diagonal and one more instrument is electron detector rotating on a circular scale and is connected to a sensitive galvanometer to record the amount of current. Please like our facebook page http://www.facebook.com/tutorvista
Views: 205081 TutorVista
Centre Of Gravity - Defintion, Examples, Experiment
 
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Follow us at: https://plus.google.com/+tutorvista/ Center of Gravity The center-of-gravity (CG) is the point at which an aircraft would balance if it were possible to suspend it at that point. It is the mass center of the aircraft, or the theoretical point at which the entire weight of the aircraft is assumed to be concentrated. Its distance from the reference datum is determined by dividing the total moment by the total weight of the aircraft. The center-of-gravity point affects the stability of the aircraft. To ensure the aircraft is safe to fly, the center-of-gravity must fall within specified limits established by the manufacturer Center of gravity is calculated as follows: •Determine the weights and arms of all mass within the aircraft. •Multiply weights by arms for all mass to calculate moments. •Add the moments of all mass together. •Divide the total moment by the total weight of the aircraft to give an overall arm. The arm that results from this calculation must be within the arm limits for the center of gravity that are dictated by the manufacturer. If it is not, weight in the aircraft must be removed, added (rarely), or redistributed until the center of gravity falls within the prescribed limits. For the sake of simplicity, center of gravity calculations are usually performed along only a single line from the zero point of the reference datum, usually the line that represents the roll axis of the aircraft (to calculate fore-aft balance). In complex situations, more than one line may be separately calculated, e.g., one calculation for fore-aft balance and one calculation for left-right balance. Weight is calculated simply by adding up all weight in the aircraft. This weight must be within the allowable weight limits for the aircraft. The weight and moment of fixed portions of the aircraft (engines, wings, etc.) does not change and is provided by the manufacturer. The manufacturer also provides information facilitating the calculation of moments for fuel loads. Other removable weight must be properly accounted for in the calculation by the operator. In larger aircraft, weight and balance is often expressed as a percentage of mean aerodynamic chord, or MAC. For example, assume that by using the calculation method above, the center of gravity (CG) was found to be 76 inches aft of the aircraft's datum and the leading edge of the MAC is 62 inches aft of the datum. Therefore, the CG lies 14 inches aft of the leading edge of the MAC. If the MAC is 80 inches in length, the percentage of MAC is found by calculating what percentage 14 is of 80. In this case, one could say that the CG is 17.5% of MAC. If the allowable limits were 15% to 35%, the aircraft would be properly loaded. Check us out for more info: http://www.tutorvista.com/content/physics/physics-i/forces/center-gravity.php Follow us at: https://twitter.com/TutorVista http://www.facebook.com/tutorvista
Views: 292998 TutorVista
What is Eddy Current? Equation, Formula, Experiment, Effects
 
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What is Eddy Current Eddy currents are currents induced in conductors to oppose the change in flux that generated them. It is caused when a conductor is exposed to a changing magnetic field due to relative motion of the field source and conductor; or due to variations of the field with time. This can cause a circulating flow of electrons, or a current, within the body of the conductor. These circulating eddies of current create induced magnetic fields that oppose the change of the original magnetic field due to Lenz's law, causing repulsive or drag forces between the conductor and the magnet. The stronger the applied magnetic field, or the greater the electrical conductivity of the conductor, or the faster the field that the conductor is exposed to changes, then the greater the currents that are developed and the greater the opposing field. The term eddy current comes from analogous currents seen in water when dragging an oar breadthwise: localised areas of turbulence known as eddies give rise to persistent vortices. Eddy currents, like all electric currents, generate heat as well as electromagnetic forces. The heat can be harnessed for induction heating. The electromagnetic forces can be used for levitation, creating movement, or to give a strong braking effect. Eddy currents can often be minimised with thin plates, by lamination of conductors or other details of conductor shape. Check for more info: https://www.tutorvista.com/content/physics/physics-iv/electromagnetic-induction/eddy-currents.php Please like our Facebook page http://www.facebook.com/tutorvista
Views: 1195581 TutorVista
Optical Fibres
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://www.tutorvista.com/content/physics/physics-iv/communication-systems/optical-fibres.php Optical Fiber An optical fiber is made up of the core (carrying the light pulses), the cladding (reflecting the light pulses back into the core) and the buffer coating (protecting the core and cladding from moisture, damage, etc). Together, all of this creates a fiber optic which can carry up to 10 million messages at any time using light pulses. Fiber optics is the overlap of applied science and engineering concerned with the design and application of optical fibers. Optical fibers are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communications. Fibers are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. Fibers are also used for illumination, and are wrapped in bundles so they can be used to carry images, thus allowing viewing in tight spaces. Specially designed fibers are used for a variety of other applications, including sensors and fiber lasers. Light is kept in the core of the optical fiber by total internal reflection. This causes the fiber to act as a waveguide. Fibers which support many propagation paths or transverse modes are called multi-mode fibers (MMF), while those which can only support a single mode are called single-mode fibers (SMF). Multi-mode fibers generally have a larger core diameter, and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 550 meters (1,800 ft). Joining lengths of optical fiber is more complex than joining electrical wire or cable. The ends of the fibers must be carefully cleaved, and then spliced together either mechanically or by fusing them together with an electric arc. Special connectors are used to make removable connections. Please like our facebook page http://www.facebook.com/tutorvista
Views: 150881 TutorVista
Coulomb's Torsion Balance
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://physics.tutorvista.com/electricity-and-magnetism/coulomb-s-law.html Coulomb's Torsion Balance The torsion balance, also called torsion pendulum, is a scientific apparatus for measuring very weak forces, usually credited to Charles-Augustin de Coulomb, who invented it in 1777, but independently invented by John Michell sometime before 1783 Its most well-known uses were by Coulomb to measure the electrostatic force between charges to establish Coulomb's Law, and by Henry Cavendish in 1798 in the Cavendish experiment to measure the gravitational force between two masses to calculate the density of the Earth, leading later to a value for the gravitational constant. The torsion balance consists of a bar suspended from its middle by a thin fiber. The fiber acts as a very weak torsion spring. If an unknown force is applied at right angles to the ends of the bar, the bar will rotate, twisting the fiber, until it reaches an equilibrium where the twisting force or torque of the fiber balances the applied force. Then the magnitude of the force is proportional to the angle of the bar. The sensitivity of the instrument comes from the weak spring constant of the fiber, so a very weak force causes a large rotation of the bar. In Coulomb's experiment, the torsion balance was an insulating rod with a metal-coated ball attached to one end, suspended by a silk thread. The ball was charged with a known charge of static electricity, and a second charged ball of the same polarity was brought near it. The two charged balls repelled one another, twisting the fiber through a certain angle, which could be read from a scale on the instrument. By knowing how much force it took to twist the fiber through a given angle, Coulomb was able to calculate the force between the balls. Determining the force for different charges and different separations between the balls, he showed that it followed Coulomb's law. To measure the unknown force, the spring constant of the torsion fiber must first be known. This is difficult to measure directly because of the smallness of the force. Cavendish accomplished this by a method widely used since: measuring the resonant vibration period of the balance. If the free balance is twisted and released, it will oscillate slowly clockwise and counterclockwise as a harmonic oscillator, at a frequency that depends on the moment of inertia of the beam and the elasticity of the fiber. Since the inertia of the beam can be found from its mass, the spring constant can be calculated. Coulomb first developed the theory of torsion fibers and the torsion balance in his 1785 memoir, Recherches theoriques et experimentales sur la force de torsion et sur l'elasticite des fils de metal &c. This led to its use in other scientific instruments, such as galvanometers, and the Nichols radiometer which measured the radiation pressure of light. In the early 1900s gravitational torsion balances were used in petroleum prospecting. Today torsion balances are still used in physics experiments. In 1987, gravity researcher A.H. Cook wrote: The most important advance in experiments on gravitation and other delicate measurements was the introduction of the torsion balance by Michell and its use by Cavendish. It has been the basis of all the most significant experiments on gravitation ever since. Please like our facebook page http://www.facebook.com/tutorvista
Views: 128675 TutorVista
Ruther's Alpha Scattering Experiment2
 
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Follow us at: https://twitter.com/TutorVista Check us out at http://chemistry.tutorvista.com/nuclear-chemistry/rutherford-scattering.html Rutherford Scattering Rutherford bombards a thin gold foil with high fastly moving positively charged alpha particles. Alpha particles are produces from a radioactive source. Whenever the alpha particles pass through the thin foil of gold, the following observations are made by Rutherford. Please like our facebook page http://www.facebook.com/tutorvista
Views: 363160 TutorVista
Intrinsic And Extrinsic Semi Conductors1
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://www.tutorvista.com/content/physics/physics-iv/semiconductor-devices/intrinsic-semiconductors.php Intrinsic Semiconductor An intrinsic semiconductor is one, which is pure enough that impurities do not appreciably affect its electrical behavior. In this case, all carriers are created due to thermally or optically excited electrons from the full valence band into the empty conduction band. Thus equal numbers of electrons and holes are present in an intrinsic semiconductor. Electrons and holes flow in opposite directions in an electric field, though they contribute to current in the same direction since they are oppositely charged. Hole current and electron current are not necessarily equal in an intrinsic semiconductor, however, because electrons and holes have different effective masses (crystalline analogues to free inertial masses). The concentration of carriers is strongly dependent on the temperature. At low temperatures, the valence band is completely full making the material an insulator. Increasing the temperature leads to an increase in the number of carriers and a corresponding increase in conductivity. This characteristic shown by intrinsic semiconductor is different from the behavior of most metals, which tend to become less conductive at higher temperatures due to increased phonon scattering. An extrinsic semiconductor is one that has been doped with impurities to modify the number and type of free charge carriers. Please like our facebook page http://www.facebook.com/tutorvista
Views: 92773 TutorVista
Satellite Communication - Defintion, Principle, Polar Circular orbit
 
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Satellite Communication Satellite communication is the branch of telecommunication which establishes and communication using satellites across the globe.We can divide the whole satellite communication into two parts namely space segments and earth segments.Satellite communication uses highly sophisticated and secured communication methods and algorithms.In satellite communication we use microwave frequencies ranging from 1GHz to 40 GHz which is further divided into various bands.In satellite communication we use multiplexing techniques such as FDMA,TDMA,CDMA etc which enables the bandwidth utilization.In the process of design we have to consider many parameters such as path loss,propagation loss,noise factors,atmospheric loss etc. Checkout for more information: https://www.tutorvista.com/content/physics/physics-ii/space-exploration/communication-satellites.php Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
Views: 362103 TutorVista
Alpha, Beta and Gamma Radiations
 
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Check out us at:http://chemistry.tutorvista.com/nuclear-chemistry/gamma-decay.html Alpha, Beta and Gamma Radiations The radiation is the process in which all the waves or energetic particles travels through a certain medium or space. The radiations are classified into two distinct types. One is ionizing and other is non-ionizing. The radiation word is mainly used to refer the ionizing radiation only. The ionization radiation have the sufficient energy to ionize any atom. Non ionization radiations are referred as visible light or radio waves. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
Views: 78814 TutorVista
Young's Double Slide Experiment
 
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Young's Double Slit Experiment Thomas Young's double slit experiment was extremely important in the area of wave theory. His experiment proves that light exhibits wavelike properties. Monochromatic light, light consisting of one color, is split using two slits placed close together. Two coherent light waves emerge on the other side of the slits. Coherent light, meaning the waves have the same frequency and phase, will both constructively and destructively interact. This interaction causes light and dark fringes based on simple geometry. If this pattern is in fact the result of the experiment, light is proven to have wavelike properties. The light and dark fringes are caused by the difference in phase of the light when it is incident on an object (i.e. light sensor). The light from the bottom slit has farther to travel and therefore a phase difference exists between the two rays of light. This interaction between these two waves creates a light, dark, or intermediate fringe. An area where a light fringe occurs, the phase difference between the two coherent light waves is zero degrees. For example, there is no phase difference and the waves add together to create a fringe with maximum intensity. An area where a dark fringe occurs, the phase difference between the two coherent light waves is equal to 180 degrees. At this point, the waves add together and completely cancel each other out. Intermediate fringes occur when the phase difference is somewhere between zero and 180 degrees. In general, intensity of the fringe decreases as the phase difference between the two light waves increases from zero to 180 degrees. Checkout for more information: https://www.tutorvista.com/content/physics/physics-iv/optics/youngs-double-slit.php Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
Views: 264984 TutorVista
Frasch Process for Extraction of Sulphur
 
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Check out us at:http://chemistry.tutorvista.com Frasch Process for Extraction of Sulphur Sulphur is extracted from underground deposits by pumping superheated steam (-440 K) down the beds to melt the element and then blowing out the molten sulphur with compressed air. This process is known as Frasch process. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
Views: 58156 TutorVista
Perfect Black Body and Its Spectrum
 
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Check us out at http://physics.tutorvista.com/light/visible-light-spectrum.html Black Body Radiation Spectrum A perfect black body is one which absorbs all the radiation emitted on it and do not reflects any. The spectrum obtained by the black body is called Black body spectrum. It is obtained by plotting graph of Wavelength along x-axis and Intensity along y-axis. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
Views: 43115 TutorVista
Faraday's Rotation Experiment
 
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Check out us at: http://www.tutorvista.com/content/physics/physics-iv/electromagnetic-induction/motional-emf.php Faraday's Law The induced emf is equal to the negative rate of change of magnetic flux through the coil. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
Views: 32153 TutorVista
Short Circuit
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://physics.tutorvista.com/electricity-and-magnetism/electric-circuit.html Short Circuit It is a low resistance offered by the conductor supplying excessive amount of current due to the direct contact between any two points in any circuit. It may lead to damage of components due to the bypassing the whole circuit. Please like our facebook page http://www.facebook.com/tutorvista
Views: 126027 TutorVista
Bernoulli's Theorem - Definition, Applications and Experiment
 
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Bernoulli's Theorem Application Bernoulli's principle states that for an inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.[1][2] Bernoulli's principle is named after the Dutch-Swiss mathematician Daniel Bernoulli who published his principle in his book Hydrodynamica in 1738. Bernoulli's principle can be applied to various types of fluid flow, resulting in what is loosely denoted as Bernoulli's equation. In fact, there are different forms of the Bernoulli equation for different types of flow. The simple form of Bernoulli's principle is valid for incompressible flows (e.g. most liquid flows) and also for compressible flows (e.g. gases) moving at low Mach numbers. More advanced forms may in some cases be applied to compressible flows at higher Mach numbers (see the derivations of the Bernoulli equation). Bernoulli's principle can be derived from the principle of conservation of energy. This states that in a steady flow the sum of all forms of mechanical energy in a fluid along a streamline is the same at all points on that streamline. This requires that the sum of kinetic energy and potential energy remain constant. If the fluid is flowing out of a reservoir the sum of all forms of energy is the same on all streamlines because in a reservoir the energy per unit mass (the sum of pressure and gravitational potential ρ g h) is the same everywhere. Fluid particles are subject only to pressure and their own weight. If a fluid is flowing horizontally and along a section of a streamline, where the speed increases it can only be because the fluid on that section has moved from a region of higher pressure to a region of lower pressure; and if its speed decreases, it can only be because it has moved from a region of lower pressure to a region of higher pressure. Consequently, within a fluid flowing horizontally, the highest speed occurs where the pressure is lowest, and the lowest speed occurs where the pressure is highest. Check for more info: http://www.tutorvista.com/content/physics/physics-iii/solids-and-fluids/bernoullis-theorem-application.php Follow us at: https://twitter.com/TutorVista https://www.facebook.com/tutorvista
Views: 852647 TutorVista
Respiratory Organs In Amphibians
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://www.tutorvista.com/biology-help Frog Respiratory Organs The frog is covered by a soft, thin, moist skin composed of two layers, an outer epidermis and an inner dermis (see Skin). The skin does not merely protect the frog but helps in respiration (see Respiratory System). An extensive network of blood vessels runs throughout the frog's skin. Oxygen can pass through the membranous skin, thereby entering directly into the blood. When a frog submerges beneath the water, all its respiration takes place through the skin. Oxygen is obtained directly from the water. The frog does not breathe through its skin alone. Adult frogs have paired, simple, saclike lungs. As in man, air enters the body through two nostrils, passes through the windpipe, and is received by the lungs (see Lungs). The mechanism of breathing, however, is different in the frog from that in man. In humans breathing is aided by the ribs, the diaphragm, and the chest muscles. The frog has no ribs or diaphragm, and its chest muscles are not involved in breathing. A frog may breathe by simply opening its mouth and letting air flow into the windpipe. However, it may also breathe with its mouth closed. The floor of the mouth is lowered, causing the frog's throat to "puff out." When the nostrils open, air enters the enlarged mouth. Then, with nostrils closed, the air in the mouth is forced into the lungs by contraction of the floor of the mouth. Please like our facebook page http://www.facebook.com/tutorvista
Views: 83473 TutorVista
Buoyant Force
 
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Define Buoyant Force Explanation: When the object is removed, the volume that the object occupied will fill with fluid. This volume of fluid must be supported by the pressure of the surrounding liquid since a fluid can not support itself. When no object is present, the net upward force on this volume of fluid must equal to its weight, i.e. the weight of the fluid displaced. When the object is present, this same upward force will act on the object. The net force on the object is given by, * When the density of the object is less than that of the fluid, the net force will be upwards and the object will rise. A Helium filled balloon is a good example. Floating Objects: When an object is floating, the net force on it will be zero. This happens when the volume of the object submerged displaces an amount of liquid whose weight is equal to the weight of the object. A ship made of steel can float because it can displace more water than it weighs. Thus the fraction of a floating object that is submerged stand in ratio to the density of the object to the density of the fluid. For objects with a vertical wall around the outside edge like a rectangle, we can reduce the above equation even farther, Checkout for more information: https://physics.tutorvista.com/fluid-dynamics/buoyancy.html Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
Views: 244021 TutorVista
Exocrine Gland and Endocrine Glands
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://www.tutorvista.com/content/biology/biology-iv/chemical-coordination-animals/endocrine-glands.php Exocrine Glands Exocrine glands are glands that secrete their products (excluding hormones and other chemical messengers) into ducts (duct glands) which lead directly into the external environment. They are the counterparts to endocrine glands, which secrete their products (hormones) directly into the bloodstream (ductless glands) or release hormones (paracrines) that affect only target cells nearby the release site. Exocrine glands contain a glandular portion and a duct portion, the structures of which can be used to classify the gland. •The duct portion may be branched (called compound) or unbranched (called simple). •The glandular portion may be tubular, acinar, or may be a mix of the two (called tubuloacinar). If the glandular portion branches, then the gland is called a branched gland. Endocrine glands are glands of the endocrine system that secrete their products, hormones, directly into the blood rather than through a duct. The main endocrine glands include the pituitary gland, pancreas, ovaries, testes, thyroid gland, and adrenal glands. The hypothalamus is a neuroendocrine organ. Other organs which are not so well known for their endocrine activity include the stomach, which produces such hormones as ghrelin. Local chemical messengers, not generally considered part of the endocrine system, include autocrines, which act on the cells that secrete them, and paracrines, which act on a different cell type near by. Please like our facebook page http://www.facebook.com/tutorvista
Views: 187919 TutorVista
levigation and Hydraulic Washing
 
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Check us out at http://chemistry.tutorvista.com/inorganic-chemistry/metallurgy.html Hydraulic Washing Hydraulic Washing Machine: In this machine hydraulic classifiers consist of vibrating sloped table with grooves is there and the particles are poured over it with a jet of water. The denser particles settle down in the grooves while the lighter particles are washed away. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
Views: 22068 TutorVista
Preparation Of Oxygen Using Hydrogen Peroxide
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://www.tutorvista.com/content/chemistry/chemistry-iii/hydrogen/hydrogen-peroxide-properties.php Chemical Properties of Hydrogen Peroxide Place the hydrogen peroxide solution in the flask. Ad a small amount of manganese dioxide or other suitable catalyst to speed up the decomposition of the hydrogen peroxide. Note that the solution is bubbling. Light a candle or a burner. Holding a wood splint with tongs, light the end of the wood splint. Allow it to burn for a few seconds until you notice that the end of the wood splint is glowing red. Blow out the flame. Insert the glowing end of the wood splint into the flask. If sufficient oxygen has been generated, the wood splint will burst into flame. Withdraw the burning splint from the flask. This demonstration can be repeated several times until the reaction has ceased. EXPLANATION This reaction is the catalytic decomposition of hydrogen peroxide: 2 H2O2 → 2 H2O + O2 This is the classic test for oxygen gas. Please like our facebook page http://www.facebook.com/tutorvista
Views: 168883 TutorVista
Moving Coil Suspended Type Galvanometer
 
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Moving Coil Suspended Type Galvanometer A moving coil galvanometer consists of a strong horse - shoe magnet with concave shaped poles N and S . A rectangular coil of insulated copper wire wound on a non - conducting frame is suspended between the magnetic poles by means of a phosphor - bronze thread P from a torsion head T1 . A small mirror M is fitted to the thread a little above the coil . The phosphor - bronze has high Young's modulus and very low rigidity modulus . Hence , it can easily be twisted but cannot be elongated . The lower end of coil is connected to a binding spring T2 . A soft iron cylinder I is a placed inside the coil without any connection with the coil . Checkout for more information: https://www.tutorvista.com/content/physics/physics-iv/moving-charges-magnetism/moving-coil-galvanometer.php Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
Views: 80255 TutorVista
Absorption and Adsorption - Definition, Difference, Examples
 
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Absorption And Adsorption Adsorption is the adhesion of molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate (the molecules or atoms being accumulated) on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid. The term sorption encompasses both processes, while desorption is the reverse of adsorption. Similar to surface tension, adsorption is a consequence of surface energy. In a bulk material, all the bonding requirements (be they ionic, covalent, or metallic) of the constituent atoms of the material are filled by other atoms in the material. However, atoms on the surface of the adsorbent are not wholly surrounded by other adsorbent atoms and therefore can attract adsorbates. The exact nature of the bonding depends on the details of the species involved, but the adsorption process is generally classified as physisorption (characteristic of weak van der Waals forces) or chemisorption (characteristic of covalent bonding). Adsorption is present in many natural physical, biological, and chemical systems, and is widely used in industrial applications such as activated charcoal, capturing and using waste heat to provide cold water for air conditioning and other process requirements (adsorption chillers), synthetic resins, increase storage capacity of carbide-derived carbons for tunable nanoporous carbon, and water purification. Adsorption, ion exchange, and chromatography are sorption processes in which certain adsorbates are selectively transferred from the fluid phase to the surface of insoluble, rigid particles suspended in a vessel or packed in a column. Check out for more info: http://www.tutorvista.com/content/biology/biology-iv/animal-nutrition/assimilation.php Follow us at: https://twitter.com/TutorVista https://www.facebook.com/tutorvista
Views: 517921 TutorVista
Freely Falling Objects and Acceleration Due to Gravity
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://physics.tutorvista.com/motion/free-fall.html Freely Falling Objects are the objects falling due to the force of gravity. The Acceleration produced in the object due to gravity is called gravitational acceleration and is denoted by g which has the value of 9.8 * 10^8 m/s^2. There are many experiments on free falling objects. Aristotle an ancient greek philosopher found that heavier objects reach earth earlier than lighter objects. This was disproved by Galileo who experimented on leaning tower of pisa by dropping the two objects one of heavier weight and other of lighter one simultaneously and observed that both the objects hit the ground simultaneously. He thus concluded that freely falling body fall on the ground ireespective of mass. Please like our facebook page http://www.facebook.com/tutorvista
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Brownian Motion - Defintion, Example, Experiment, Applications
 
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Brownian Motion Brownian motion (named after the Scottish botanist Robert Brown) or pedesis is the seemingly random movement of particles suspended in a fluid (i.e. a liquid such as water or air) or the mathematical model used to describe such random movements, often called a particle theory. The mathematical model of Brownian motion has several real-world applications. An often quoted example is stock market fluctuations. However, movements in share prices may arise due to unforeseen events which do not repeat themselves, and physical and economic phenomena are not comparable. Brownian motion is among the simplest of the continuous-time stochastic (or random) processes, and it is a limit of both simpler and more complicated stochastic processes (see random walk and Donsker's theorem). This universality is closely related to the universality of the normal distribution. In both cases, it is often mathematical convenience rather than the accuracy of the models that motivates their use. Check out for more info: http://chemistry.tutorvista.com/physical-chemistry/brownian-motion.html Follow us at: http://www.facebook.com/tutorvista
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Production of Laser
 
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Laser Production Laser technology enables us to excite the electrons so they jump to a higher energy level and stimulate them to drop back to a particular lower energy level in order to obtain the required wavelength of the radiation. Checkout for more information: https://www.tutorvista.com/content/physics/physics-iv/communication-systems/laser-works.php Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
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Electrostatic  Shielding
 
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Check us out at http://www.tutorvista.com/content/physics/physics-iv/electrostatic-potential-capacitance/electrostatics-conductor.php Electrostatic Shielding The demonstration is conducted by setting up the TESV instrument on the tripod, turning on and zeroing the instrument, and then bringing the plastic rod, charged up by rubbing, close to the sensing head. As expected, the instrument responds by indicating the presence of charge. The TESV is then covered by one of the antistatic plastic bags and the experiment repeated. Refer to the photograph shown above. Now, the instrument registers little or no charge. Even when a charged conducting object is discharged directly to the bag, the instrument registers little or nothing. The explanation of this phenomenon is that the instrument has been shielded from the electrostatic field of the charged object by the conductive bag. Note that it is not necessary to ground the bag. If grounding were necessary, antistatic bags would be much less convenient and effective than they are. Grounding is unnecessary here because electric charge abhors the inside surface of any void enclosed by conductive material. For an ungrounded bag, the charge simply stays on the outside where it harmlessly remains. Now consider the problem of removing a sensitive electronic component or board from a charged bag. If the bag is handled by a person, contact with the hand serves to ground the bag and remove the charge. However, if the person wears insulating gloves, then the component may draw a strong electrical spark as it is withdrawn from the bag and may be damaged. Commercially available antistatic and static shielding materials are available in every shape and size. In addition to thickness, abrasion resistance, and so forth, the technical specifications usually refer to either MIL specs or some measure of the rate of charge dissipation. Definitions for antistatic materials abound and sometimes can be confusing. For a summary of these, please click here. Refer to the advertisement shown just below. This bag has a metallic layer which provides "Faraday Cage" shielding, in reference to the above cited fact that charge abhors the inside surface of a conductor (as long as there is no charge within the bag). Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
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Photoelectric Effect and Photoelectric Cell
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://physics.tutorvista.com/modern-physics/photoelectric-effect.html Define Photoelectric Effect When light falls on any surface it emits electrons. This effect is known as Photoelectric effect the phenomena is given in 1887 by H.Hertz. Photoelectric Cell The cell which converts the light ebnregy into the electric energy is called as Photoelectric cell. Please like our facebook page http://www.facebook.com/tutorvista
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Cathode Ray Oscilloscope - Defintion, Experiment, Examples, Applications, Uses
 
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Cathode Ray Oscilloscope The cathode ray oscilloscope is used as an animation in the laboratories. Since it is more reliable, stable and ease of operation , the animation of the cathode ray oscilloscope is used in lab. The animation of the cathode ray oscilloscope which is used in the lab provide the measurement of voltage signals. Check out us at: http://www.tutorvista.com/content/physics/physics-ii/modern-physics/cathode-rays.php Follow us at: https://twitter.com/TutorVista http://www.facebook.com/tutorvista
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DC Motor
 
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Follow us at: https://twitter.com/TutorVista Check us out at http://www.tutorvista.com/content/science/science-ii/magnetic-effects-electric-current/electric-motor.php DC Motor A direct current (DC) motor is a fairly simple electric motor that uses electricity and a magnetic field to produce torque, which turns the motor. At its most simple, a DC motor requires two magnets of opposite polarity and an electric coil, which acts as an electromagnet. The repellent and attractive electromagnetic forces of the magnets provide the torque that causes the DC motor to turn. If you've ever played with magnets, you know that they are polarized, with a positive and a negative side. The attraction between opposite poles and the repulsion of similar poles can easily be felt, even with relatively weak magnets. A DC motor uses these properties to convert electricity into motion. As the magnets within the DC motor attract and repel one another, the motor turns. A DC motor requires at least one electromagnet. This electromagnet switches the current flow as the motor turns, changing its polarity to keep the motor running. The other magnet or magnets can either be permanent magnets or other electromagnets. Often, the electromagnet is located in the center of the motor and turns within the permanent magnets, but this arrangement is not necessary. To imagine a simple DC motor, think of a wheel divided into two halves between two magnets. The wheel of the DC motor in this example is the electromagnet. The two outer magnets are permanent, one positive and one negative. For this example, let us assume that the left magnet is negatively charged and the right magnet is positively charged. Electrical current is supplied to the coils of wire on the wheel within the DC motor. This electrical current causes a magnetic force. To make the DC motor turn, the wheel must have be negatively charged on the side with the negative permanent magnet and positively charged on the side with the permanent positive magnet. Because like charges repel and opposite charges attract, the wheel will turn so that its negative side rolls around to the right, where the positive permanent magnet is, and the wheel's positive side will roll to the left, where the negative permanent magnet is. The magnetic force causes the wheel to turn, and this motion can be used to do work. When the sides of the wheel reach the place of strongest attraction, the electric current is switched, making the wheel change polarity. The side that was positive becomes negative, and the side that was negative becomes positive. The magnetic forces are out of alignment again, and the wheel keeps rotating. As the DC motor spins, it continually changes the flow of electricity to the inner wheel, so the magnetic forces continue to cause the wheel to rotate. DC motors are used for a variety of purposes, including electric razors, electric car windows, and remote control cars. The simple design and reliability of a DC motor makes it a good choice for many different uses, as well as a fascinating way to study the effects of magnetic fields. Please like our facebook page http://www.facebook.com/tutorvista
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Solar Water Heater
 
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Check out us at:http://www.tutorvista.com/content/physics/physics-ii/fission-and-fusion/solar-water-heater.php Solar Water Heater System Solar water heater consists of an insulated box which is painted black from inside and in which copper tubes are fitted in the form of a coil. These copper tubes are painted black from outside. The box and copper tubes of the solar water heater are painted black so that they may absorb heat rays of the sun more efficiently. The box is covered with a glass lid to prevent the loss of heat due to convection and radiation. The glass lid of the box produces green house effect in the solar water heater and traps heat rays of the sun. The two ends of the copper tube of the solar water heater are joined to a water storage tank. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista
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Solar Cooker
 
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Check out us at:http://www.tutorvista.com/content/physics/physics-ii/fission-and-fusion/solar-cooker.php What is a Solar Cooker A solar cooker contains a wooden box having thermocol lining from inside. A box made aluminium is placed inside the wooden box. The inner side of the aluminium box is painted black. The top is closed by a glass sheet. A plane mirror is fixed to the hinged lid. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
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Cleansing Action Of Soap
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://chemistry.tutorvista.com Cleansing Action Of Soap Chemically, a soap is a sodium salt of a long chain carboxylic acid (fatty acid) which has cleaning properties in water. A soap has a large non-ionic hydrocarbon group and an ionic group, COO-Na+. E.g. Sodium stearate (C17H35COO-Na+), Sodium oleate (C17H33COO-Na+), Sodium palmitate (C15H31COO-Na+) etc. The process of making soap by hydrolysis of fats and oils with alkalies is called saponification. Please like our facebook page http://www.facebook.com/tutorvista
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Zone Refining
 
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Check out us at:http://chemistry.tutorvista.com/organic-chemistry/petroleum-refining.html Zone Refining This technique is based on the standard that the impurities are more soluble in the melt than in the sold of the melt. A circle mobile heater is fixed at one end of a rod of the impure metal. The molten zone moves along with the header which moves forward. Impurity to get concentration, this method is very useful for producing semiconductor and other metals of very high purity. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
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Simple Microscope
 
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Check out us at:http://www.tutorvista.com/content/physics/physics-ii/optical-instruments/simple-microscope.php Define Simple Microscope A simple microscope is one of the simplest of all the optical instruments. It consists of a single convex lens of short focal length. The object to be seen by the simple microscope is kept just inside the focus of the lens. When viewed from the other side, a virtual, erect and enlarged image of the object is seen. Magnifying power (M) of the simple microscope is given by M = 1 + D / f Where, D is the least distance of distinct vision (it is equal to 25 cm for normal human eye) and f is the focal length of the convex lens. When the eye is fully relaxed, the magnification of the simple microscope is given by M = D / f Simple microscope is used as a magnifier for watch repairers, specimen observers, palmists etc. Simple microscope cannot be used to observe the tiny objects like virus and bacteria. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
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Proof of Converse Of Pythagoras Theorem
 
02:22
Check us out at http://math.tutorvista.com/geometry/converse-of-pythagorean-theorem.html Converse of Pythagoras Theorem The Pythagorean theorem or Pythagoras' theorem is a relation in Euclidean geometry among the three sides of a right triangle (right-angled triangle). In terms of areas, it states: In any right triangle, the area of the square whose side is the hypotenuse (the side opposite the right angle) is equal to the sum of the areas of the squares whose sides are the two legs (the two sides that meet at a right angle). The theorem can be written as an equation relating the lengths of the sides a, b and c : where c represents the length of the hypotenuse, and a and b represent the lengths of the other two sides. These two formulations show two fundamental aspects of this theorem: it is both a statement about areas and about lengths. Tobias Dantzig refers to these as areal and metric interpretations. Some proofs of the theorem are based on one interpretation, some upon the other. The Pythagorean theorem is named after the Greek mathematician Pythagoras, who by tradition is credited with its discovery and proof although it is often argued that knowledge of the theorem predates him. (There is much evidence that Babylonian mathematicians understood the formula, although there is little surviving evidence that they fitted it into a mathematical framework. Please like our facebook page http://www.facebook.com/tutorvista
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Application Of Eddy Currents
 
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Check us out at http://www.tutorvista.com/content/physics/physics-iv/electromagnetic-induction/application-eddy-currents.php Eddy Current Applications Eddy currents are currents induced in conductors to oppose the change in flux that generated them.[citation needed] It is caused when a conductor is exposed to a changing magnetic field due to relative motion of the field source and conductor; or due to variations of the field with time. This can cause a circulating flow of electrons, or a current, within the body of the conductor. These circulating eddies of current create induced magnetic fields that oppose the change of the original magnetic field due to Lenz's law, causing repulsive or drag forces between the conductor and the magnet. The stronger the applied magnetic field, or the greater the electrical conductivity of the conductor, or the faster the field that the conductor is exposed to changes, then the greater the currents that are developed and the greater the opposing field. The term eddy current comes from analogous currents seen in water when dragging an oar breadthwise: localised areas of turbulence known as eddies give rise to persistent vortices. Eddy currents, like all electric currents, generate heat as well as electromagnetic forces. The heat can be harnessed for induction heating. The electromagnetic forces can be used for levitation, creating movement, or to give a strong braking effect. Eddy currents can often be minimised with thin plates, by lamination of conductors or other details of conductor shape. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
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Different Types Of Magnetic Substances
 
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Check us out at http://physics.tutorvista.com/electricity-and-magnetism/types-of-magnets.html Types of Magnets Magnetic substances are substances containing aligned dipoles. Dipoles are spinning electrons. In order for something to be magnetic, its dipoles must be aligned with each other, so that they face the same direction. The direction they face create a North end, while the opposite end creates a South end. Some substances, known as ferromagnetic substances, have permanently aligned dipoles. Other substances, such as paramagnetic and dimagnetic substances, require an external magnetic field to align, or 'induce' the dipoles of the substance. To conclude, magnetic substances contain dipoles which are permanently aligned, or can be aligned through the force of external magnetic fields. Magnetic forces are forces that arise from the movement of electrical charge. Maxwell's equations and the Biot-Savart law describe the origin and behavior of the fields that govern these forces. Thus, magnetism is seen whenever electrically charged particles are in motion. This can arise either from movement of electrons in an electric current, resulting in "electromagnetism", or from the quantum-mechanical spin and orbital motion of electrons, resulting in what are known as "permanent magnets". Electron spin is the dominant effect within atoms. The so-called 'orbital motion' of electrons around the nucleus is a secondary effect that slightly modifies the magnetic field created by spin. The magnetic force is actually due to the finite speed (the speed of light) of a disturbance of the electric field which gives rise to forces that appear to be acting along a line at right angles to the charges. In effect, the magnetic force is the portion of the electric force directed to where the charge used to be. For this reason magnetism can be considered to be basically an electric force that is a direct consequence of relativity. Source(s): Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
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Change of State and Specific Latent Heat
 
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Check out us at: http://physics.tutorvista.com/heat/latent-heat.html Change of State and Specific Latent Heat The latent heat is the amount of heat absorbed or released by a substance when it undergoes a change of state without a change in the temperature of the substance or its surroundings. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
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Properties of Colloids
 
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Check out us at:http://chemistry.tutorvista.com/physical-chemistry/colloids.html Properties of Colloids A Colloidal system is made of two phases. The substance distributed as colloidal particles is called dispersed phase or discontinuous phase or internal phase, The continuous phase in which the colloidal particles are dispersed is called dispersion medium or external phase...( i.e., Colloidal solution= Dispersed phase + Dispersed medium) Ex: Colloidal solution of Copper in water, Carbohydrate solution and Proteins. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
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Hydraulic Press - Pascal's law, Working, Experiment, Uses, Observation
 
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Hydraulic Press Hydraulic press is a machine consisting of a cylinder fitted with a piston that uses liquid under pressure to exert a compressive force upon a stationary base plate. The liquid is forced into the cylinder by a pump. First we discussed what is mean by hydraulic, it is a topic in applied science and engineering dealing with the mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics press is used for the generation, control, and transmission of power by the use of pressurized liquids. Hydraulic topics range through most science and engineering disciplines, and cover concepts such as pipe flow, dam design, fluidics and fluid control circuitry, pumps, turbines, hydropower, computational fluid dynamics, flow measurement, river channel behavior and erosion. Checkout for more information: https://www.tutorvista.com/content/physics/physics-iii/solids-and-fluids/pascals-law-applications.php Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
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Van De Graaff Generator - Definition, Principle, Experiment, Example
 
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How Does a Van De Graaff Generator Work Van de graaff generator produces a continuous supply of charge on a large metal dome when a rubber belt is driven by an electric motor or by hand which is show in the figure. For example pens and combs made of certain plastics become charged when rubbed on your sleeve and can then attract scraps of paper. Checkout for more information: http://www.tutorvista.com/content/physics/physics-iv/electrostatic-potential-capacitance/van-de-graff-generator.php Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
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Interference
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://physics.tutorvista.com/waves/constructive-interference.html Interference When two coherent sources (same frequency / wavelength) of light superimpose, then the resultant is of bright and dark bands known as interference pattern. When the two sources of light superimpose in a certain region of space, then the total energy is redistributed in such a way that at certain point's intensity will be maximum and at other it is minimum. Define Interference: Interference can be defined as the variation of intensity in the region of superposition of two or more coherent sources. Please like our facebook page http://www.facebook.com/tutorvista
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Comets, Meteors, Meteorites and Asteroids
 
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Check us out at:http://www.tutorvista.com/content/physics/physics-ii/universe/asteroids-meteoroids-and-comets.php Comets, Meteors, Meteorites and Asteroids Comets are the small icy bodies that are present in the solar system which are very close to the Sun. Comets displays the visible coma. A coma is a thin fuzzy and temporary atmosphere and it is also a tail sometimes. These both phenomenon are due to the solar wind and the solar radiation effects on the comet's nucleus. The nuclei of the comet themselves loose the particles such as dust, ice and small rock particles which are collected by the comets. Please like our facebook page http://www.facebook.com/tutorvista Follow us at: https://plus.google.com/+tutorvista/
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Law Of Conservation Of energy in a Simple Pendulum
 
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Law of Conservation of Energy in a Simple Pendulum A pendulum is hanging body from the fixed point which if pulled and then released will swing due back and forth. Consevation of energy states that the momentum of the body before oscillation is equal to the momentum after oscillation. If we go through simple pendulum experiment. At Initial point of pendulum total energy = mgh At intermediate point of pendulum total energy = 1/2 mv^2 At end point pf pendulum total energy = mgh Hence the conservation of energy in simple pendulum is given by ∑ (P.E_bO + KE_bO) = ∑ (PE_aO + KE_aO) Where P.E_bo = Potential energy before oscillation, K.E_bo = Kinetic energy before oscillation, P.E_ao = Potential energy after oscillation, K.E_ao = Kinetic energy after oscillation. Checkout for more information: https://www.tutorvista.com/content/physics/physics-i/measurement-and-experimentation/simple-pendulum.php Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
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Alimentary canal and Action of enzymes
 
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Tube through which food passes in animals it extends from the mouth to the anus and forms a large part of the digestive system. In human adults, it is about 9 m/30 ft long, consisting of the mouth cavity, pharynx, oesophagus, stomach, and the small and large intestines. It is also known as the gut. It is a complex organ, specifically adapted for digestion and the absorption of food. Enzymes from the wall of the canal and from other associated organs, such as the pancreas, speed up the digestive process. The muscles in the wall of the alimentary canal contract, mixing food with the enzymes and slowly pushing it along in the direction of the anus in a process known as peristalsis. Dietary fibre encourages this movement. The constant stream of enzymes from the canal wall and from the pancreas assists the breakdown of food molecules into smaller, soluble nutrient molecules, which are absorbed through the canal wall into the bloodstream and carried to individual cells. The wall of the canal receives an excellent supply of blood and is folded so as to increase its surface area. These two adaptations ensure efficient absorption of nutrient molecules.Enzymes are proteins that catalyze (i.e., increase the rates of) chemical reactions.[1][2] In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, called the products. Almost all processes in a biological cell need enzymes to occur at significant rates. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell. Like all catalysts, enzymes work by lowering the activation energy (Ea‡) for a reaction, thus dramatically increasing the rate of the reaction. Most enzyme reaction rates are millions of times faster than those of comparable un-catalyzed reactions. As with all catalysts, enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of these reactions. However, enzymes do differ from most other catalysts by being much more specific. Enzymes are known to catalyze about 4,000 biochemical reactions.[3] A few RNA molecules called ribozymes also catalyze reactions, with an important example being some parts of the ribosome.[4][5] Synthetic molecules called artificial enzymes also display enzyme-like catalysis.[6] Enzyme activity can be affected by other molecules. Inhibitors are molecules that decrease enzyme activity; activators are molecules that increase activity. Many drugs and poisons are enzyme inhibitors. Activity is also affected by temperature, chemical environment (e.g., pH), and the concentration of substrate. Some enzymes are used commercially, for example, in the synthesis of antibiotics. In addition, some household products use enzymes to speed up biochemical reactions (e.g., enzymes in biological washing powders break down protein or fat stains on clothes; enzymes in meat tenderizers break down proteins, making the meat easier to chew). Checkout for more information: https://www.tutorvista.com/content/science/science-ii/nutrition/alimentary-canal.php Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
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Real Depth and Apparent Depth
 
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Index of Refraction Definition The index of refraction of light in a particular medium is calculated with respect to another optical medium. For the sake of generalization, the commonly referred term "index of refraction" of a particular medium denotes the index of refraction of that medium calculated with respect to air/vacuum. This is more specifically known as the "absolute index of refraction" for a particular medium. We can calculate index of refraction by its definition: "Index of refraction can also be defined as the ratio of the speed of light in the first medium to the speed of light in the second medium". Checkout for more information: https://physics.tutorvista.com/light/index-of-refraction.html Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
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Surface Tension - Defintion, Experiment, Observation, Example
 
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What is Surface Tension Surface tension is the property of the free surface of a liquid at rest behave like a stretched membrane in order to acquire minimum surface area. Surface tension can be defined as the force acting per unit length perpendicular on an imaginary line drawn on the liquid surface, tending to pull the surface apart along the line. Its unit is N m^-1 and dimensional formula is MT^-2. The property of Surface Tension gives rise to an interesting phenomenon known as capillarity. Capillarity is nothing but the rise of a liquid in a capillary tube. Examples of Capillarity are blotting paper absorbs ink, the oil in the lamp rises up the wick and the sponge retains water. Checkout for more information: https://physics.tutorvista.com/fluid-dynamics/surface-tension.html Follow us at: https://www.facebook.com/tutorvista https://twitter.com/TutorVista
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Laboratory Preparation Of Hydrogen
 
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Follow us at: https://plus.google.com/+tutorvista/ Check us out at http://chemistry.tutorvista.com/ Hydrogen H2 is produced in chemistry and biology laboratories, often as a by-product of other reactions; in industry for the hydrogenation of unsaturated substrates; and in nature as a means of expelling reducing equivalents in biochemical reactions. Laboratory In the laboratory, H2 is usually prepared by the reaction of acids on metals such as zinc with Kipp's apparatus. Zn + 2 H+ -- Zn2+ + H2 Aluminium can also produce H2 upon treatment with bases: 2 Al + 6 H2O + 2 OH− -- 2 Al(OH)−4 + 3 H2 The electrolysis of water is a simple method of producing hydrogen. A low voltage current is run through the water, and gaseous oxygen forms at the anode while gaseous hydrogen forms at the cathode. Typically the cathode is made from platinum or another inert metal when producing hydrogen for storage. If, however, the gas is to be burnt on site, oxygen is desirable to assist the combustion, and so both electrodes would be made from inert metals. (Iron, for instance, would oxidize, and thus decrease the amount of oxygen given off.) The theoretical maximum efficiency (electricity used vs. energetic value of hydrogen produced) is between 8094%. 2H2O(aq)-- 2H2(g) + O2(g) In 2007, it was discovered that an alloy of aluminium and gallium in pellet form added to water could be used to generate hydrogen. The process also creates alumina, but the expensive gallium, which prevents the formation of an oxide skin on the pellets, can be re-used. This has important potential implications for a hydrogen economy, since hydrogen can be produced on-site and does not need to be transported. Please like our facebook page http://www.facebook.com/tutorvista
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