Electromagnetism

• When an electric current flows through a wire, it creates a magnetic field around the wire.
• The Chinese were the first to build compasses to help them navigate, using an important property found in certain materials that had been discovered centuries before.
• Magnetism, the force exerted by magnets when they attract or repel each other, became known to people many centuries ago.
• The black metallic ore called lodestone has a property of attracting iron particles to it, making it a naturally magnetized piece of the mineral magnetite.
• Over the course of centuries, much of the mystery that once surrounded magnetism has been dispelled, and the lodestone or the natural magnet is no longer familiar in the study of magnetism.
• A magnet is a substance that possesses magnetic properties, attracting iron and facing the same direction when moving freely.
• Ferromagnetic substances like iron, steel, nickel, and cobalt are strongly attracted to magnets.
• Lodestones are magnetite or natural all-natural magnets are permanent magnets, meaning they will never lose their magnetic power.
• An alnico magnet is a permanent magnet containing aluminum, nickel, and cobalt.
• Permanent magnets are used in radio speakers, audio video devices, and other electrical appliances.
• Artificial magnets are materials that can be made into magnets, made by induced magnetism, a process called magnetization.
• There are two types of artificial magnets: temporary and permanent.
• Temporary magnets are magnets that aren't always magnetic but their magnetism can be turned on at will.
• Permanent magnets are those magnets whose magnetic strength never fades.
• Examples of permanent artificial magnets include refrigerator magnets and neodymium magnets, the strongest permanent magnets commercially available.
• Temporary magnets are those of soft iron that are easy to magnetize and they lose their magnetic property very easily.
• An electromagnet is an example of a temporary magnet, used to lift heavy objects in industrial sites and in forwarding businesses.
• Every magnet has two poles, and the areas of greatest magnetic force are called magnetic poles.
• The end of the magnet that points north is called the north magnetic pole and the end that points south is the south magnetic pole.
• Opposite poles attract, same poles repel, this is another characteristic of magnets.
• There are six elements that can be made into magnets: iron, nickel, cobalt, aluminum, gadolinium, and dysprosium.
• To make a permanent magnet, you need an alloy, an alloy is a mixture of two or more metals.
• The classic material for making a permanent magnet is steel, an alloy of carbon and iron.
• There are two types of magnets,
• Magnetism is the force exerted by magnets when they attract or repel each other, a magnet is a substance that possesses magnetic properties.
• Opposite poles attract and same poles repel in magnets.
• Orson's law states that an electromagnet is a magnet that can be switched on and off, it is a solenoid with a core.
• Orsted discovered that an electric current is surrounded by a magnetic field, leading him to conclude that a current carrying wire produces a magnetic field.
• The process of generating current by the relative motion between a wire and a magnetic field is called electromagnetic induction.
• There are many types of electric motors, each designed for a particular purpose or use, all operating on the principle of electromagnetism.
• Electromagnetic induction is the production of an electromotive force across an electrical conductor in a changing magnetic field.
• There are two types of magnets, natural and artificial, with artificial magnets further classified as temporary or permanent.
• A generator operates on the principle of electromagnetic induction, converting mechanical energy to electrical energy.
• The strength of an electromagnet can be made stronger by increasing the number of turns on the core.
• An electric motor is a device that converts electrical energy to mechanical energy, operating on the principle of electromagnetism.
• Michael Faraday discovered that a moving wire through a magnetic field could produce an electric current, leading him to conclude that when a wire is moved through a magnetic field a current is generated in the wire.
• Ships use compasses to find the correct course through vast areas of oceans where no land is in sight, a ship's compass is a permanent magnet attached to a card marked in degrees that float in alcohol.
• Magnets are flexible and can be made into many sizes and shapes, there are several magnets hidden inside your house: electric motors, loudspeakers, and television sets.
• The closer you bring two magnets together, the stronger the force between them becomes, move them apart and the force gets weaker if you move them further from each other you will eventually feel no force.
• A magnetic field is the space around a magnet in which its force affects objects, this is a magnetic field around a bar magnet, the arrow heads show the direction of the magnetic lines of force which come out of the end pole and enter the s-pole, the concentration of the lines of force at the poles shows that the field is strongest there.