state the directions for the Faraday's law experiment
Answers
Faraday’s Law was proposed by great experimental physicist and chemist Michael Faraday. The Faraday’s laws of electromagnetic induction are the results of Faraday’s experiments. Faraday performed three main experiments to discover the phenomenon of electromagnetic induction.
In the first experiment, he proved that when the strength of the magnetic field is varied then only the induced current is produced. An ammeter is connected to a loop of wire; the ammeter deflects when a magnet is moved towards the wire.
In the second experiment he proved that when the current is passed through the iron rod, it becomes an electromagnet. He noticed that when there is a relative motion between the magnet and the coil, induced electromagnetic force is produced. When the magnet is rotated about its axis, no electromotive force is observed and if the magnet is rotated about its own axis then the induced electromotive force is produced. Thus, there is no deflection in the ammeter when the magnet is held stationary.
In the third experiment, he noticed that galvanometer does not show any deflection and no induced current is produced in the coil when the coil is moved in a stationary magnetic field. The ammeter deflects in the opposite direction when the magnet is moved away from the loop.
If we move a magnet to and fro in the vicinity of a conductor (for example a coil connected with a galvanometer) we find electricity is generated in the coil without contact with the magnet. Thus it is called electromagnetic induction.
A change in magnetic flux (or number of lines of force = φ ) through a metal surface or a circuit induces an emf in it and this phenomenon is called electromagnetic induction. Faradays law of electromagnetic induction states that the magnitude of emf (e) induced is equal to the rate of change of flux through the area of the circuit.
e = -dφ/dt
The polarity of the induced emf is explained by the Lenzs law. The law states that the emf induced is such that it opposes the change that has induced it.