Magnetism is a set of physical properties mediated by magnetic fields. Electric currents and elementary particle magnetic moments combine to form a magnetic field, which operates on other currents and magnetic moments. Magnetism is a component of the larger phenomena of electromagnetic. The most well-known effects occur in ferromagnetic materials, which are highly attracted by magnetic fields and may be magnetised to become permanent magnets, hence creating magnetic fields. It is also feasible to demagnetize a magnet. Only a few materials are ferromagnetic; the most frequent are iron, cobalt, nickel, and their alloys. Less common examples are the rare-earth elements neodymium and samarium. Because permanent magnetism was discovered in lodestone, a kind of natural iron ore known as magnetite, Fe3O4, the prefix ferro- refers to iron.
Magnetism may be found in all substances. The bulk susceptibility of magnetic materials is categorised. Although ferromagnetism is responsible for the majority of the effects of magnetism experienced in everyday life, there are numerous forms of magnetism. Paramagnetic materials, such as aluminium and oxygen, are weakly attracted to a magnetic field; diamagnetic materials, including copper and carbon, are weakly repelled; and antiferromagnetic materials, such as chromium and spin glasses, have a more complicated connection with a magnetic field. The force of a magnet on paramagnetic, diamagnetic, and antiferromagnetic materials is generally too faint to be felt and can only be measured by laboratory tools, hence these substances are frequently referred to as non-magnetic in normal language.
The magnetic state of a material is affected by temperature, pressure, and the magnetic field applied. As these factors alter, a material may display more than one type of magnetism.
Although the exact mathematical connection between strength and distance varies, the intensity of a magnetic field nearly always decreases with distance. Magnetic fields can become complex as a result of different combinations of magnetic moments and electric currents.
Although some theories anticipate the occurrence of magnetic monopoles, only magnetic dipoles have been seen.
There are a number of physical phenomena that are associated with the presence and movement of matter that is charged with electricity. Magnetism and electricity are connected because they are both part of the phenomena of electromagnetic, as defined by Maxwell’s equations. Lightning, static electricity, electric heating, electric discharges, and many more common phenomena are all connected to electricity.
An electric field is created by the existence of an electric charge, which can be positive or negative. An electric current and a magnetic field are generated when electric charges travel.
When a charge is placed in an area with a non-zero electric field, a force operates on it. The magnitude of this force is determined by Coulomb’s law. The electric field will exert force on a moving charge. Thus, we may talk about electric potential at a certain place in space, which is equal to the work done by an external agent in transferring a unit of positive charge from an arbitrarily determined reference point to that position without any acceleration and is commonly measured in volts.
Although electrical activities have been studied since antiquity, theoretical advancement has been modest until the seventeenth and eighteenth centuries. The electromagnetic theory was developed in the nineteenth century, and by the end of that century, electrical engineers had put electricity to be utilized in industrial as well as home applications. The fast advancement of electrical technology during this period changed industry and society, propelling the Second Industrial Revolution. Because of electricity’s incredible adaptability, it can be used in an almost infinite number of applications, including transportation, heating, lighting, communications, and calculation. Electricity is now the lifeblood of modern industrial civilization.
The Greek terms Elektron, which signifies “amber,” and magnetic lithos, which translates “Magnesian stone,” which is magnetic iron ore, are the roots of the phrase “electromagnetism.” The ancient Greeks were aware of electricity and magnetism, but they thought of them as separate entities.
Know how to solve this question:
Assertion(A): If the filament of a light bulb is not uniform horizontal its life is shortened.
Reason(R): Resistance of glowing light bulb is less than that of bulb at room temperature.
Electromagnetism was not defined until James Clerk Maxwell released A Treatise on Electricity and Magnetism in 1873. Maxwell’s work includes twenty renowned equations, which were later reduced to four partial differential equations. The following are the basic notions represented by the equations:
- Charges that are similar to one another repel, whereas charges that are unlike to one another attract. Inversely proportionate to their squared distance, the attraction or repulsion between them is a powerful force.
- Magnetic poles are usually found in north-south pairs. Like poles repel each other whereas dissimilar poles attract each other.
- An electric current flowing through a wire creates a magnetic field surrounding it. The magnetic field’s direction is determined by the current’s direction. The “right hand rule” states that the magnetic field direction follows the fingers of your right hand if your thumb is pointed in the current direction.
- Moving a wire loop toward or away from a magnetic field causes a current to flow through the wire. The direction of the stream is determined by the direction of movement.
Despite the fact that Maxwell’s theory defied Newtonian mechanics, investigations have verified Maxwell’s equations. Einstein’s theory of special relativity eventually settled the debate.
