Electromagnetic wave from Maxwells equations in free space

In summary, Maxwell's equations state that in a region with no charge or current, the divergence of the electric field is 0 and the curl of the electric field is equal to the negative change in magnetic flux over time. Similarly, the divergence of the magnetic field is 0 and the curl of the magnetic field is equal to the product of the electric permittivity and the change in electric field over time. These conditions may seem confusing, but they are necessary for understanding how electromagnetic waves are created. While charges and currents are needed to generate these waves, they can still be observed in regions without sources due to the differential and integral forms of Maxwell's equations.
  • #1
Melac12
6
0
My textbooks says in a region where there is no charge or current Maxwell's equations read
divergence of E=0
Curl of E=-dB/dt all d are partial
Divergence of B=0
Curl of B=ue(dE/dt)

I get the math of showing that there are waves, but I don't get some of these conditions. 1st don't you need a charge in the 1st place to create an electric field? and then doesn't that charge have to move to created a magnetic field, which would be current? I mean with no charge and no current what makes the electric and magnetic field?
I hear that light can be made by taking an electron and shaking it. Electron being an electron has charge and shaking it make the magnetic field. If that not right one demonstrate light form electron?
 
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  • #2
You do need charges to create an electromagnetic wave. However, even if you are in a perfect vacuum far away from that charge you can still have electromagnetic fields which will satisfy the conditions you cite above.
 
  • #3
The differential equations operate locally at a given point in space. While you need a charge or current to generate the electromagnetic waves, you can observe them in regions where there are no sources. The integral form of Maxwell's equations represent integrations over surfaces and volumes and make it easier to see how the equations operate in regions containing sources.
 

Related to Electromagnetic wave from Maxwells equations in free space

1. What are Maxwell's equations?

Maxwell's equations are a set of four fundamental equations that describe the behavior of electromagnetic fields. They were developed by James Clerk Maxwell in the 19th century and are considered to be one of the cornerstones of modern physics.

2. What is an electromagnetic wave?

An electromagnetic wave is a type of wave that is created by the oscillation of electric and magnetic fields. These waves can travel through empty space and do not require a medium. Examples of electromagnetic waves include light, radio waves, and X-rays.

3. What role do Maxwell's equations play in the study of electromagnetic waves?

Maxwell's equations provide a mathematical framework for understanding and predicting the behavior of electromagnetic waves. They describe how electric and magnetic fields interact with each other and how they propagate through space. Without Maxwell's equations, our understanding of electromagnetic waves would be significantly limited.

4. What is meant by "free space" in relation to electromagnetic waves?

In the context of Maxwell's equations, free space refers to a region of space that is not affected by any external electric or magnetic fields. This allows for a simplified analysis of electromagnetic waves, as they are not influenced by any external factors.

5. How are Maxwell's equations applied in real-world situations?

Maxwell's equations have numerous applications in modern technology, including telecommunications, radar, and medical imaging. They are also used in the development of new materials and technologies, such as metamaterials and wireless power transmission. Understanding and manipulating electromagnetic waves has greatly impacted our daily lives and continues to drive advancements in various fields of science and technology.

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