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SAA A SR, , CHAPTER 6, , ELECTROMAGNETIC INDUCTION, , INTRODUCTION harges of currents can pro,, t moving char. he reverse effec, In 1820 Oersted found tha re made to find the r © effect i., : after many attempts We tric current. Around, ee = rm, England and Jose electric field or clans, emer tae all magnetic field can ne > led to the FP eclopr, current. The pioneering experiments of Faraday an a, modern day generators and transformers., , Whenever the magnetic flux lin, e.m.f is induced in the circuit. This ph, induction. The e.m.f induced in the circuit 1, due to the induced e.m.f is called induced current., , IQ, , a, , ked with a closed circuit change, ,, henomenon is called electromagney, s called induced e.m.f and the cur,, , , , , , , THE EXPERIMENTS OF FARADAY AND HENRY, , 1. Coil - magnet Experiment Fig.6.], Consider a closed circuit using a Coil and a eeonter, , Introduce the North Pole of a magnet into the coil. The Ss eaela ’, shows a deflection indicating a current through the circuit. When Re, , magnet is stationary inside the coil, there is no deflection in re, galvanometer. i.e., no current flows through the circuit. When the North G @, Pole is removed, the galvanometer shows an opposite deflection. This 1, indicates a current in the circuit in opposite direction. When the South |, Pole is introduced, the deflection will be opposite to that when North Pole 4, introduced. When the South Pole is removed, the deflection is opposite to that whe, , the North Pole is removed., , Conclusions, , 1) When the magnet is introduced or removed, the magnetic flux associated with, coil changes. This change of magnetic flux is responsible for the induced e.m/J., 2) When the magnet is stationary inside the coil, there is no change of flux. Hen, there is no induced e.m,f., , 3) The deflection is more when the magnet is moved faster., , 2. Coil-Coil Experiment n, , B, Consider two coils A and B kept close as shown in (—, figure. A closed circuit is formed using a cell and a key K with =, the coil A. The coil B is closed through a galvanometer. When, , the key is pressed, the galvanometer shows a sudden | =, deflection. When the key is kept closed, the galvanometer {S, shows no deflection. When the key is released galvanomet =, shows a sudden deflection in the opposite direction, dal