Oersted Experiment


Oersted Experiment 


It was a Danish physicist, named Hans Christian Oersted , who in 1820 discovered that there is a relationship between electricity and magnetism . Oersted showed that the moving electrons can create a magnetic field by setting up a compass needle through a wire carrying an electric current.

 According to Hans Christian Oersted, The magnetic field which is created by the current goes in circles around the wire.

Oersted Experiment , Oersted's  Experiment
Oersted Experiment

Oersted Experiment

Oersted first of all observed the relationship between the electricity and the magnetism , with the help of following experiment :

Step 1 : 

In first step, take a conducting wire represented by AB. Now place the wire above the magnetic needle in such a way that the wire should be parallel to the magnetic needle. When there is no current in the conducting wire, then there is no deflection in the magnetic needle

Step 2:

When the current flows through the wire from point A to  point  B, then the north pole of the magnetic needle is deflected towards the left side. And in the similar way, when the current starts to flow from point B to point  A, then the N-pole of the magnetic needle is deflected towards right side. 
This clearly proves that the magnetic field is produced around the current carrying conductor, which deflects the magnetic needle. 

step 3:

With the help of Rheostat , when we increase the current in the wire, we note that the deflection of the magnetic needle is increased and vice - versa. 

This step proves that the strength of a magnetic field increases with the increase in current and vice- versa.

Step 4:

This step shows that when the wire AB is held perpendicular to the magnetic needle, and the current is allowed to pass though the wire AB, then the magnetic needle is not deflected.
This shows that, in this case, a magnetic field is parallel to the magnetic needle and hence there is no deflection of the magnetic needle. 

Step 5:

Further studies showed that the magnetic field consists of magnetic lines of force which are in the form of concentric circles.

Step 6:

Further, when current carrying wire is placed above and parallel to the magnetic needle, then the magnetic needle is deflected in a particular direction. 

Also, when the current carrying wire is placed below and parallel to the magnetic needle, then the needle is deflected in the opposite direction. 

This is due to the fact that the direction of the magnetic field above the conductor is opposite to the direction of a magnetic field below the conductor. 

Step 7:

The direction of magnetic field is given by Ampere's  Swimming Rule :

According to this rule, if we imagine a man swimming along the wire in the direction of current with his face turned towards the magnetic needle, so that the electric current enters through his feet and leaves from his head, then the N-pole of the magnetic needle is deflected towards his left hand. This rule can be recollected with the help of a word SNOW. It means, the current from South to North ,in a conducting wire over the magnetic needle , the north pole is deflected towards west. 

Oersted Experiment ,Oersted's  Experiment
Oersted's Experiment

Oersted Experiment

Step 8:      

   Results : 

From Oersted experiment we find that :

A)    A current carrying conductor produces a magnetic field. 

B)   Larger the value of current in the conductor, the stronger is the magnetic field and vice versa. 

C)  From this experiment, it was also found that the magnetic field is always produced at right angle to the current carrying conductor. 

D)  Magnetic lines of force are always in the form of concentric circles with the current carrying conductor at the center place. 

E)  A charge at rest produces an electric field where as the charge in motion produces both the electric field and the magnetic field. 


This article Provide you information about Oersted experiment . It also provides you information related to its results and concept of Ampere's  Swimming Rule. It also informs you how  Hans Christian Oersted discovered a relationship between electricity and magnetism

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