Magnetism and Electromagnetism Assignment Help




Magnetism is a property of materials that respond at an atomic or subatomic level to an applied magnetic field.

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Introduction:

        Artificial magnets: Artificial magnets are produced by charge the specimens of a suitable ferromagnetic substances in current carrying coils.

Types of artificial magnets are

  • Permanent magnets
  • Temporary magnets:

Permanent magnets: The magnets which have their magnetic properties for a long period is called permanent magnets.

Temporary magnets: The magnets which have their magnetic properties for a short period of time is called temporary magnets.

Permanent Magnets:

Permanent magnets:

        Permanent magnets are the magnets produced by ferromagnetic substances keeping their magnetic properties for a long duration.

Characteristics of permanent magnets:

  • Retentivity is high – produce strong magnetic field.
  • Coercivity is high – the magnetization is not wiped out by strong external fields, mechanical ill-treatment and temperature changes.

Electromagnets:

Temporary magnets:

        It is also known as electromagnets. Temporary magnets are magnets created by ferromagnetic substances having the magnetic properties for a very short duration.

Example: Soft iron core

The material which is used for core of the electromagnets having the following properties.

  • Intensity of magnetism is high with small magnetic field
  • Initial permeability is high
  • Coercivity is low
  • Retentivity is high

Construction of electromagnet:

        To construct the electromagnet the soft iron core is kept inside the solenoid. The current is passed along the solenoid. This process produces the magnetic field. The magnetism produced in this circuit is present if and only if the current is passes along the solenoid. If the current is stopped to pass then the magnetism will be destroyed. Hence the soft iron core is considered as electromagnet.

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Factors affecting the strength of an electromagnet:

  • Current passing in the coil: The electromagnet is increased when the current passing in the coil is increased.
  • Number of turns in the coil: The electromagnet is increased when the number of coils in the core is increased.
  • Material of core: The soft iron core is placed among the current carrying coil for increase the strength of the electromagnets.

Applications of electromagnets:

  • Electric bell
  • Telephone
  • Electric motor

Electromagnetic Induction Device:

            Let us see about the Electromagnetic Induction Device. Cause of the magnetic field is done by electric current. On the basic induction experiments, the induction in a coil if the magnetic flux linked with the coil changes. This phenomenon may be easily demonstrated by Faraday’s simple experiments.  Whenever there is a change in magnetic flux linked with a coil, an emf is induced in the coil. This event is also called as electromagnetic induction. It will be explained by electromagnetic induction device.

electromagnetic induction device

                                                                                                                             

Electromagnetic Induction Device Construction:

 

Let us see the electromagnetic induction device. The apparatus consists of a coil, a galvanometer and a bar magnet. The two ends of the coil are connected to the terminals of galvanometer device.

  • When a bar magnet is placed near the coil, no deflection is observed in galvanometer.
  • When north pole of magnet is moved rapidly towards the coil, the galvanometer shows a deflection. When magnet is stopped, the deflection in galvanometer becomes zero. When speed of magnet is increased, the deflection is increased.
  • When north pole of magnet is taken away from the coil rapidly, the galvanometer device shows a deflection, but in opposite direction. When magnet is stopped, deflection becomes zero and when it is moved faster, the deflection increases.
  • Similarly when the south pole of magnet faces the coil and the magnet is moved towards or away from the coil, the galvanometer again shows the deflection but now in directions opposite to (2nd and 3rd)
  • When number of turns in coil is increased or soft iron core is placed inside the coil, the current in the coil increases.
  • Now magnet is kept stationary and coil is moved towards or away from the magnet, even then there is a deflection in the galvanometer.

 

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Electromagnetic Induction Device Observation:

Clearly, the galvanometer device shows a deflection when there is a relative motion between the magnet and the coil. The electromagnetic force (emf) is induced in the coil only when the magnetic flux linked with the coil increases, the current in the coil is induced in one direction and when it decreases the current in the coil flows in opposite direction. The current increases with rate of increase of magnetic flux and decrease with rate of decrease of magnetic flux linked with the coil.

Electromagnetic Waves

         Electromagnetism is defined when the combination of modulating electric also magnetic field produced by accelerating charge to propagate not in as of these charge on the speed of light within the structure of effect.  Earth’s surroundings be generally affect by the different type of waves such as power waves, radio waves, microwaves and so on.  Let us see the electromagnetic waves form.

Electromagnetic Waves Form

         Water waves, earthquake waves, and sound waves each requires an average or else material during which to circulate. These are example of automatic waves. Light be able to and exist describe like waves- waves of altering electric with magnetic field to spread outer as of their source. This electromagnetic wave though performs not need be in middle. They spread at 3, 000, 000, 00 meters per second during space. Electromagnetic waves are the transverse waves.

        Within simpler terms, the altering electric with magnetic fields swing vertical in the direction of each further and the way of the propagate waves.

Most excellent electromagnetic waves:

        Most excellent basis of electromagnetic waves is the accelerated waves. An accelerated charges be one namely rising or else lessening its speed or altering its way of motion or else equally. Permit us visualize two charges on break within the area of both other.

        They are absorbed within all others electric force ground. But one charge unexpectedly begin in the direction of swing up with down, second charge experience the alter in the ground of the first charge following a few very little limited time elapse. Oscillate charge be accelerate.

       The moving charge’s electric fields alter, since perform their magnetic fields. These altering electric also magnetic fields produce all other during Faraday’s law of initiation also Ampere’s law. These altering fields separate as of the oscillate charge with spread not in into space on the speed of light.

  • Whole spectrums of electromagnetic waves exist, which range as of extremely small frequency wavelength in the direction of extremely elevated wavelength.
  • Every wavelength is as a group referred toward when electromagnetic wavelengths also not just the fine range of wavelengths also frequencies recognized when visible light.


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