Learning Management

  Fit India Movement topic for Group Discussion

    Induction Motor(AC motor) :                  An induction motor or asynchronous motor is an AC electric motor in which the electric current is the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. Types of Induction motor :       The types of induction motors can be classified depending on whether they are a single phase (or) three phase induction motor. Single Phase Induction motors : Split Phase Induction motor Capacitor Start Induction motor Capacitor Start & Capacitor Run Induction motor Shaded Pole Induction motor Three Phase Induction motor : Squirrel Cage Induction motor Slip Ring Induction motor Single Phase Induction motor             The single phase induction machine is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps and so forth.              The Single-Phase induction motor stator has a laminated iron core with two windings arranged perpendicu

  Group Discussion

  Total internal reflection               When the angle of incidence is greater than  the critical angle, the light ray gets reflected into the denser medium at the interface i.e., light never enters the rarer medium. This phenomenon is called  total internal reflection.   Applications of total internal reflection: 1.Brilliance of Diamonds :  Total internal reflection is the main reason for brilliance of diamonds. The critical angle of a diamond is very low(22.4). So, if a light ray enters a diamond it is very likely to undergo total internal reflection which makes the diamond shine.                                   2.Optical fibres  :  Total internal reflection is the basic principle behind working of optical fibre. An optical fibre is a thin fibre made of glass (or) plastic having radius about a micrometre. A bunch of such thin fibres form a light pipe.             Because of the small radius of the fibre, light going into it makes a nearly glancing incidence on the wall. The angle

  Mirages         Mirage is an optical illusion where it appears that water has collected on the road at a distant place but when we get there, we don't find any water. Do you know the reason why it appears  so?   Let us see...                                                     The formation of a mirage is the best example where refractive index of a medium varies throughout the medium.             During a hot summer day, air just above the road surface is very hot and the air at higher altitudes is cool.It means that the temperature decreases with height. As a result density of air increases with height.We know that refractive index of air increases with density. Thus refractive index of air increases with height. So, the cooler air at the top has greater refractive index than hotter air just above the road. Light travels faster through thinner hot air than through the denser cool air above it.                                                                                     W

    " Metallurgy is the process of extraction of metals from their ores".        Human history in terms of materials had the Bronze Age and Iron Age pertaining to the metals they started to use the bronze and iron. Now we have more than 75% metals among the elements available. Occurence of metals in nature          The earth crust is the major source of metals.Sea water also contains some soluble salts such as sodium chloride and megnesium chloride etc,.Some metals like gold(Au), silver(Ag), and copper(Cu) are avaible in nature in free state as they are least reactive.Other metals mostly found in nature in the combined form due to their more reactivity. The elements or compounds of the metals which occur in nature in earth crust are called Minerals. At some places, minerals contain a very high percentage of a particular metal and the metal can be profitably extracted from it.The minerals from which the metals are extracted from it. The minerals from which the metals are extra