When current flows through a wire, the wire generates a magnetic field around it, which can be detected by a compass needle placed nearby. This magnetic field causes the compass needle to deflect from its north-south alignment. The deflection is due to the interaction between the magnetic field created by the current in the wire and the magnetic field of the compass needle.
Explanation:
1. Magnetic Field Generation:
When electric current flows through a wire, the moving electric charges create a magnetic field around it. This is known as the magnetic effect of electric current.
2. Compass Needle Interaction:
A compass needle is essentially a small magnet. It aligns itself with the Earth’s magnetic field, pointing towards the magnetic north pole.
3. Deflection:
When the compass needle is placed near a wire carrying current, the magnetic field of the wire interacts with the magnetic field of the compass needle. This interaction causes the compass needle to deviate from its original north-south orientation. The direction of deflection depends on the direction of the current in the wire.
4. Oersted’s Experiment:
This phenomenon was first discovered by Hans Christian Oersted, who observed that a compass needle deflected when placed near a wire carrying current.
Key Points:
The deflection of the compass needle is a direct result of the magnetic field produced by the current-carrying wire.
The strength and direction of the magnetic field depend on the magnitude and direction of the current.
This principle is fundamental to understanding electromagnetism and is used in various applications, such as electric motors and generators.