Electromagnetic induction is the production of electric current in a conductor when it cuts through a magnetic field
When a conductor cuts through a magnetic field the change in the magnetic field induces emf across the conductor. The induced emf causes induced current to flow.
The cause of electromagnetic induction
The magnetic field in the conductor interacts with the external magnetic field. The resultant magnetic force causes a force on the electrons in the conductor. This causes movement of the electrons and thus current to flow.
Magnetic flux
Number of magnetic lines passing through a given closed surface.
Factors that determine the magnitude of electromagnetic induction.
rate of change of magnetic flux linkage- increase in magnetic flux linkage increases with magnitude of induced emf
Number of turns of the coil- increases with increase
Angle the conductor cuts the field- is maximum when conductor cuts the magnetic field perpendicularly
Faraday's law
the magnitude of induced emf is directly proportional to the rate of change of magnetic flux linkage (bicycle dynamo)
Effect of increasing the speed of motion of the conductor
The galvanometer deflects more. It increases the rate of change of magnetic flux linkage thus more induced emf causing more current to flow
WAYS TO INCREASE THE CURRENT INDUCED IN CONDUCTOR
Increase speed of motion in the conductor
Increase the number of turns of the coil
Use stronger magnet
When a side is parallel to the magnetic field it does not cut through the magnetic field
When one side is out of the field more force is required than when all the sides are in the field
