What is electromagnetic induction?,Magnetism and Electricity, Production of Induced E.M.F and current, Faraday's First and second law,Direction of Induced E.M.F. and current,Types of Induced E.M.F.

Electromagnetic Induction
Magnetism and Electricity
               Whenever an electrical current flows through a conductor a magnetic field is establish in the space which surrounds the conductor.In other words we can say that when electrons are in motion they produce a magnetic field.
                 when we place a moving conductor inside the magnetic field ,electrons are starts flowing inside the conductor.The phenomena of current produced E.M.F. .When a conductor cut magnetic field or a conductor placed in a changing magnetic field is known as electromagnetic Induction.
Production of Induced E.M.F. and Current
Condition 1
              In this condition our coil is fix and we will move the magnet.The arrangement is shown in the  fig.(a ). When both coil and magnet are stationary we will observe no deflection in the galvanometer.When we bring the magnet closer to the coil from position AB to CD we will find Little deflection in the galvanometer.When we bring the magnet permanently at position CD and no more movement in the magnet we will find  no more deflection in the galvanometer.At position CD the magnetic line of forces are stronger for coil than AB.Again when we bring the magnet from position CD to Ab as shown in the fig.(b) again we will find deflection in the galvanometer,but this deflection is in opposite direction.
                 
Fig.(a)



Fig.(b)


                This experiment conclude that E.M.F. is induced in the coil when we move the magnet and coil is stationary.
Condition 2
 
                In this condition the coil is laying inside the stationary magnetic field as shown in the fig. below .It is found that whenever we moved the coil up and down a momentary deflection is produced in the galvanometer.It means that some transient emf is induced in the coil AB.The magnitude of this induced e.m.f. depends upon the quickness of the movement of AB. One important point should be noted that if we move the coil AB in the direction parallel to the magnetic line of force(flux) in this condition coil does not cut it then no e.m.f. will be induced in the coil.


Fig.

                    From this experiment we can conclude that when-ever a conductor cuts the magnetic line of forces(flux) an emf in induced inside the conductor.
                     The phenomena of electromagnetic induction can be explained with the help of Faraday's law of electromagnetic induction .
Faraday's First Law

                    The first law of Faraday's stated that when-ever a conductor cuts magnetic flux an e.m.f. is is induced in that conductor.
Faraday's second Law

                    The second law of Faraday's stated that the magnitude of the induced e.m.f. is equal to the rate of change of flux linkages.
Direction of Induced E.M.F. and Current
   
                 We can define the relation between the direction of induced current the direction of flux and the direction of motion of the conduction with the help of Fleming's right-hand rule.
                  Fleming's right-hand rule stated that if our first finger in the direction of flux our thumb shows the motion of current then the direction of induced e.m.f. will be in the direction of our middle finger. as shown in the diagram below.


fig.

Types of Induced E.M.F.
                    The induced e.m.f. is of two types.

      1) Dynamically Induced.
      2) Statically Induced.
Dynamically Induced

               In this type of induced e.m.f. the field is stationary and the conductor cut across it.Example of dynamically induced e.m.f. is in Generator.
Statically Induced
               In this case the conductor or coil remains stationary and flux linked with it is changed.Example of statically induced e.m.f. is in transformers.


                   
     

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