Light Propagation: Electric & Magnetic Fields in Vacuum/Medium

In summary, electric and magnetic fields can be produced by electric charge or changing magnetic fields. In an electromagnetic wave, these fields sustain each other. However, for the electric or magnetic field to exist, a charge is needed. In the absence of charge, there is no electric or magnetic field. This is where concepts such as polarizability, susceptibility, and induced dipole moment come into play.
  • #1
amaresh92
163
0
light doesn't cotain any charge then how it fluctulate the electric and magnetic field in vacumn or medium.
 
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  • #2
According to Maxwell's equations, an electric field can be produced either by electric charge or by a changing magnetic field; and a magnetic field can be produced either by electric current (moving charges) or by a changing electric field. In an electromagnetic wave the continually changing electric and magnetic fields keep each other going.
 
  • #3
But for the electric or magnetic field a charge is needed.
But in vacumn in the absence of charge how light propagate as there is no question of electric or magnetic field in absence of charge.
 
  • #4
amaresh92 said:
But for the electric or magnetic field a charge is needed.

Please reread jtbell's message. You can create an electric field either with an electric charge or a changing magnetic field.
 
  • #5
amaresh92 said:
light doesn't cotain any charge then how it fluctulate the electric and magnetic field in vacumn or medium.
Light doesn't "fluctuate the electric and magnetic field", light is the fluctuations in the electro-magnetic field.
 
  • #6
amaresh92 said:
light doesn't cotain any charge then how it fluctulate the electric and magnetic field in vacumn or medium.

google "polarizibility", "susceptibility", "induced dipole moment", etc.
 
  • #7
sorry andy i didn't get u.
 

1. What is light propagation?

Light propagation refers to the movement of electromagnetic waves through space. These waves consist of electric and magnetic fields that oscillate perpendicular to each other and to the direction of the wave's travel.

2. How do electric and magnetic fields interact during light propagation?

During light propagation, electric and magnetic fields are closely intertwined and cannot exist independently. Changes in one field will cause corresponding changes in the other field, creating a self-sustaining wave.

3. What is the difference between light propagation in a vacuum and in a medium?

In a vacuum, light propagates at a constant speed of approximately 299,792,458 meters per second. In a medium, the speed of light is slower due to interactions with the atoms and molecules in the material.

4. How does the speed of light in a medium relate to its refractive index?

The speed of light in a medium is inversely proportional to the refractive index of the material. This means that as the refractive index increases, the speed of light decreases.

5. Can light propagation be affected by external factors?

Yes, external factors such as electric and magnetic fields, as well as temperature and pressure, can affect the speed and direction of light propagation. This is why light can be refracted, reflected, and diffracted when passing through different materials or encountering obstacles in its path.

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