Fisica de imanes

Chapter 3.2 E “Current can produce magnets”
In the 1800s, a Danish physicist named Hans Christian Oersted discovered that an
electric current produces a magnetic field.
ElectromagnetismElectromagnetism is magnetism that results from an electric current.
An electric current generally consists of moving electrons, a current in a wire produces a magnetic field.
The wire acts as a magnet.Increasing the amount of current in the wire increases the strength of the magnetic field.
The magnetic field lines around a wire are usually illustrated as a series of circles.
The magnetic field ofa wire actually forms the shape of a tube around the wire. The
direction of the current determines the direction of the magnetic field. If the direction of the electric current is reversed, themagnetic field still exists in circles around the wire, but is reversed.
magnetic
field

current-carrying
wire

If the wire is shaped into a loop, the magnetism becomes concentrated inside the loop.If you wind the wire into a coil, the magnetic force becomes stronger with each additional turn of wireas the magnetic field becomes more concentrated.

Current carrying
wirecoil
magnetic
field

A coil of wire with charge flowing through it has a magnetic field. Inside the coil,
the field flows in one direction, forming a northpole at one end. The flow outside the coil returns to the south pole. The direction of the electric current in the wire determines which end of the coil becomes the north pole.

Making anElectromagnet
An ELECTROMAGNET is a magnet made by placing a piece of iron or steel inside a coil of wire. As long as the coil carries a current, the metal acts as a magnet and increases the magnetic field ofthe coil.

coil iron core
By increasing the number of loops in the coil, you can increase the strength of the electromagnet. Electromagnets exert a much more powerful...