Important Facts of Magnetism

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Magnetism

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Dear Readers, Here we have given the list of Important Facts of Magnetism for competitive Exams. General Science is very important Topic for competitive Examination. In this topic, we have given about the Physics Magnetism, substance, method, definition & types. Candidates those who are preparing for the exams make use of it.

Important Facts of Magnetism 

A physical phenomenon produced by the motion of electric charge, which results in attractive and repulsive forces between objects.

Discover Magnet:  

The word magnet comes from the Greek “magnítis líthos”, which means “Magnesian Stone”. Magnesia is an area in Greece (Now Manisa, Turkey) where deposits of magnetite have been discovered since antiquity.

Property:

S.NoProperties Of Magnetism
1Magnets attract objects of iron, cobalt and nickel. 
2The force of attraction of a magnet is greater at its poles than in the middle. 
3Like poles of two magnets repel each other. 
4Opposite poles of two magnets attracts each other. 
5If a bar magnet is suspended by a thread and if it is free to rotate, its South Pole will move towards the North Pole of the earth and vice versa.

Magnet Uses:

  • Magnets are used to make a tight seal on the doors to refrigerators and freezers.
  • They power speakers in stereos, earphones, and televisions.
  • Magnets are used to store data in computers, and are important in scanning machines called MRIs (magnetic resonance imagers), which doctors use to look inside people’s bodies

Magnetic Substance:

There are three magnetic substances.There are

Magnetic SubstanceDefinitionExampleMagneic FieldTemperaure
ParamagnetFeebly magnetised in the direction of the magnetic field when placed in the strong magnetic field.Aluminium, Platinum, salts of ironStrongIncrease
DiamagnetFeebly magnetised in the oppositedirection of the magnetic field when placed in the strong magnetic field.Gold, Silver, Zinc, copperWeakNo Change
FerromagnetSubstances which are strongly magnetised in he diection of the magnetic field when placed in itIron,nickel, cobaltStrongIncrease

Making of Magnet Method:

(1) Single touch method

(2) Double touch method

(3) Using electric current.

Important Terms In Magnetism & Definitions:

Important WordsDefinitions
Magnetism it is a property of certain substances which pull closer or repel other objects.
Magnetic fieldsMagnetic fields  are produced by electric currents, which can be macroscopic currents in wires, or microscopic currents associated with electrons in atomic orbits. 
ElectromagnetismAn interaction between electricity and magnetism, as when an electric current or a changing electric field generates a magnetic field, or when a changing magnetic field generates an electric field.
Magnetic EnergyThe potential  energy  of a  magnet  of  magnetic  moment, m, in a  magnetic  field, B, is defined as the mechanical work of  magnetic  force on re-alignment of the vector of the  Magnetic  dipole moment, and is equal
ElectroMagnet An  electromagnet  is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. Electromagnets  usually consist of wire wound into a coil.
Magnetic Fluxmagnetic flux  in an area taken perpendicular to the  magnetic flux's  direction. 
Magnetic flux densityMagnetic flux density  is defined as the amount of  magnetic flux  in an area taken perpendicular to the  magnetic flux's  direction
Flux densityF lux density  is a  measure  of the force applied to a particle by the magnetic field.
Electric Flux DensityA measure of the intensity of an electric  field generated by a free  electric  charge, corresponding to the number of electric  field lines passing through a given area.
Magnetic Field StrengthThe amount of magnetizing force (how much force it has to magnetize, magnetic materials such as iron, steel, etc) is called Magnetic field strength which is denoted by (H).

Important to Know About Magnetism:

1) magnetism from the Earth’s magnetic field

2) magnetism produced through metabolism within the cells in the body.

Types of Magnetism:

S.NoTypes Of MagnetsExamplesExplanation
1TemporaryIron alloyIt can be easily magnetized by even a weak magnetic field. 
2PermanentA Horseshoe magnet, a refrigerator magnet, a freezer sealOnce they are magnetized, these objects do not easily lose their magnetism
3Electromagnetshard disk drives, speakers, motors,  and  generatorsThese are used when a very strong magnet is necessary.The Core act as a strong magnetic field

Magnetic Field & Range:

Typical magnetic fieldsTesla Range
Inside Atomic Nuclei10 11  T
Superconducting Solenoids20 T
Superconducting Coil Cyclotron5 T
Small Ceramic Magnet0.1 T
Earth's field at the equator4(10 −5 ) T
Interstellar Space2(10 −10 ) T

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