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Unit - 3 Electromagnetic Induction, , Whenever there is a change in the magnetic flux linked with a coil, an emf is induced in the, coil. This phenomenon is electromagnetic induction., , M in in mf in lenoi I mi ic in ion, > Increase the strength of the magnet., > Increase the number of turns in the solenoid., > Increase the speed of motion., , cl istics of electrici ived fi AC pc iaB, , * Direction changes continuously, * emf increases and decreases., , , , AC, , , , , , , , , , 6/18, , , , , , * Direction doesn’t change., * emf doesn’t change., , , , , , , , , , , , , , a Battery DC, * Direction doesn’t change., SE * emf increases and decreases., O, a Generator DC, A ni rr, Parts, , > NS - Magnetic Poles, , > ABCD - Armature, , > B,, B,- Graphite Brushes, > R,, R2- Slip Rings, , , , , , , , , , > Field magnet- The magnet that creates magnetic flux in the generator., , > Armature -An arrangement of insulated conducting wire wound on a soft iron core. This, can be made to rotate about an axis., , > Slip Rings- Metal rings which are welded together with the armature coil. They rotate along, with the armature on the same axis of rotation as the armature, , > Graphite Brushes -They are arrangements which always make contact with the slip rings., Current flows through them to the external circuits.