Faraday’s law explained

Faraday’s law

According to this law an induced EMF is generated in a conductor when it is placed in a variable magnetic field. In mathematical form, it can be given as 

E = -t

Here is change is magnetic flux in small time period t.

Experiment 1

The first experiment of Faraday helps us understand the current induction by the magnet. For this experiment, Faraday took a coil. The coil was connected to a galvanometer. The galvanometer he took was sensitive. The wave includes a few turns of directing material protected from one another. 

At the time of the movement of the North-pole of a bar magnet towards the curl or circle, the galvanometer associated with the loop showed a glimpse of diversion. Faraday noticed the progression of electric flow in the loop. Also, he observed that the current kept going as long as the bar magnet was moving. No diversion was shown by the galvanometer when the bar magnet didn’t move. It is significant concerning the Faraday experiment.

Additionally, when the south pole of the bar magnet is moved towards or away from the curl, the redirections in the galvanometer are reversed to that seen with the north pole for comparative developments.

Faraday also observed that the diversion or deflection of the pointer is more significant or more modest, relying on the speed with which it is pulled towards or away from the curl. A similar impact is seen when the loop is moved and the magnet is held fixed. This shows that mainly the overall movement between the magnet and the loop is the reason for the flow of current in the loop. 

Hence, Faraday concluded that at whatever point there is a general movement between a loop and a magnet, an emf is set up across the loop or a current flows through the loop. He also understood that the general movement between the magnet and the loop is enormous, and an induced electromagnet due to the current is created in the loop. Another conclusion he got was that the current keeps going in the loop as much as the movement of the magnet concerning the loop proceeds. 

Experiment 2

In his second faraday experiment, he took 2 coils and did not connect the coils. The coil which was associated with the battery was called the primary coil. Another coil that was put close to the primary one related to a sensitive galvanometer was called a secondary coil. 

The current in the coil created a steady magnetic field. That happened because of the connected battery. Faraday noticed that the system became parallel to the previous one to create the magnetic field. Then he moved the secondary coil towards the primary coil. He observed a deflection in the galvanometer’s pointer. The deflection was the proof of the electric field in the primary coil.

Also, Faraday did the reverse of the process; he moved the secondary coil away from the primary coil. In this case, he noticed that the galvanometer deflected in the opposite direction compared to the previous one. The deflection lasted for the same amount of time as the motion of the secondary coil. When Faraday did not move the secondary coil, he did not notice any deflection in the galvanometer.

Experiment 3

Faraday did the third experiment to find out whether relative motion is necessary or not between two coils or a coil and a magnet to induce a current.

Here, Faraday placed two coils. He connected one of them to the galvanometer and the other to a battery. Then, he installed a push button. When he pressed the button, he noticed deflection in the galvanometer in the primary coil. It indeed proved that there was current in the coil.

He also observed a temporary deflection when the button was not pressed. Therefore, he concluded that the change in the magnetic flux due to the difference in the primary coil is the main reason for inducing current in the second coil and the deflection in the galvanometer. 

So to sum it up on Faraday’s magnetic field induction experiment, he found no deflection in the galvanometer, and no induced current was produced in the coil when the coil was moved in a stationary magnetic field. Instead, the ammeter deflected in the opposite direction when the magnet was moved away from the loop.

Conclusion 

From all 3 experiments, it was concluded that there was relative motion between the coil and magnet, resulting in the generation of current in the coil. Faraday’s law of induction is the basic operating principle of inductions, electric generators, electric motors, power transformers, musical instruments such as electric guitar, electric violins, etc. Thus, we can say that the law of induction given by Faraday is very useful in our daily life as we deal with so many electronic devices in our daily use which are working in Faraday’s laws of electromagnetic induction.

Faraday mainly performed three experiments for the derivation of the law. In his first experiment, he explained when the strength of a magnetic field is varied only at that point in time; a current is induced. In his second experiment, he explained that electromotive force is induced when a relative motion exists between the magnet and the coil.