Oersted’s observation

Hans Christian Oersted, a Danish scientist who worked in the field of electricity and magnetism in the 1820s, established that there was a relationship between the two. Oersted demonstrated that moving electrons can generate a magnetic field by putting a compass and a wire carrying an electric current. 

Oersted’s Experiment

The experiment’s background demonstrates that it was already known that an electric current in a wire produces heat and may cause the wire to glow. 

This established a connection between the three phenomena: 

• Electricity

• Heating

• Lighting

The objective of the experiment was to demonstrate that a current-carrying wire generates a magnetic field around it :

• Rub the needle along one side of the magnet, from the centre to the pointed end.

• Make sure you massage the needle tip 30-40 times in the same direction to magnetise the tip of the needle. By attempting to pick up another needle, you can determine whether the needle magnetism is working properly. 

• Water should be added to the bowl. Place the needle on the cork and the cork in the bowl and tape the needle to the cork.

• The needle’s reaction to the magnet can be observed by swishing the magnet around the bowl. 

• Use clay to secure a wire on top of the dish. Connect one end of the wire to the switch and the other end to the (+) terminal of the “Power Pack.” This will complete the circuit. Another wire should be run from the switch to the negative (-) terminal of the “Power Pack.”

• Close the switch for a brief moment and watch how the needle travels, then re-open the switch to continue. It is not recommended to leave the switch on for extended periods.

As a result of the current flowing through the circuit when the switch is closed, a magnetic field is created around the wire. After reacting to the magnetic field in the circuit and turning perpendicular to the wire, the magnetic needle is no longer magnetic.

This particular experiment is considered to be one of the most important in the history of the use of electric power. It resulted in the discovery of electromagnetism and the invention of the electric motor which are still in use today.

Observations of Oersted Experiment 

Oersted discovered that, for a straight wire carrying a constant direct current (DC), the following is true –

• The magnetic field lines ring the current-carrying wire, preventing it from moving.

• Unlike the wire, the magnetic field lines are arranged in a plane perpendicular to the wire.

• Because of this, if the current is reversed, the magnetic field will be in the opposite direction of the current.

• The magnitude of the current has a direct relationship with the strength of the field in the area.

• The strength of the field at any given place is inversely related to the distance between the point and the wire that is being measured.

Importance of  Oersted’s Experiment

Oersted’s law is only valid for constant currents that do not change over time. As a result, it is only valid for direct current electric circuits that do not contain any capacitors or inductors. By considering the situation of a circuit consisting of a battery charging a capacitor through a resistor, it can be seen that it fails for time-varying currents. The presence of a magnetic field in this circuit may be demonstrated experimentally; however, any closed curve encircling the conductor can be spanned by a surface passing between the capacitor plates, through which no current passes and from which the equation would yield zero magnetic field. 

Maxwell amended Oersted’s rule to account for time-varying currents by including a new source term known as displacement current. The result is the Ampere–Maxwell equation, which is derived from the Ampere–Maxwell equation.

Conclusion 

It was discovered by seeing that the needle of a compass close to a current-carrying wire twisted so that the needle was perpendicular to the wire that the term “oersted observation” came to be associated with. Oersted conducted research and discovered the physical law that describes the magnetic field, which is now known as Oersted’s law, known as the discovery of Oersted’s law of induction, it was the first time that a link between electricity and magnetism had been discovered and it is considered to be the first of two laws that link the two disciplines. The other law is Faraday’s law of induction. These two principles become a part of the equations that govern electromagnetic phenomena, known as Maxwell’s equations, after their discoverer James Maxwell.