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Zubair Ahmad
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I am in trouble with this theorem. I did it from Griffith's electrodynamics but I am not getting the physics of it. So can someone explain it lucidly.
@Lord Jestocost has given some good general material on the topic. If you want more specific responses then you will need to make a more specific question. What specifically are you not getting.Zubair Ahmad said:I am not getting the physics of it
Ok, so that means that ANY system which obeys Maxwell’s equations will necessarily also obey Poynting’s theorem. It doesn’t matter if the charges are internal or external, if they move in response to the fields or in response to some other constraints, or whatever. As long as Maxwell’s equations are valid, so is Poynting’s theorem.Zubair Ahmad said:Yes that's clear to me.
Poynting's theorem in Griffith's is a fundamental law in electromagnetism that describes the relationship between the electric and magnetic fields in an electromagnetic wave. It states that the rate of change of electromagnetic energy in a given volume is equal to the negative of the electromagnetic power flowing into that volume.
Poynting's theorem involves three main components: the electric field, the magnetic field, and the Poynting vector. The electric and magnetic fields are perpendicular to each other and to the direction of propagation of the electromagnetic wave, while the Poynting vector represents the direction and magnitude of energy flow.
Poynting's theorem is used in a variety of practical applications, such as in the design and analysis of antennas, transmission lines, and other electromagnetic devices. It also plays a crucial role in understanding electromagnetic radiation and its effects on materials and living organisms.
The implications of Poynting's theorem are far-reaching and have greatly contributed to our understanding of electromagnetism. It helps explain the relationship between electric and magnetic fields, enables the calculation of energy flow in electromagnetic waves, and provides a basis for the conservation of energy in electromagnetic systems.
Poynting's theorem is unique in that it combines the concepts of electric and magnetic fields to describe the flow of electromagnetic energy. Other fundamental laws, such as Gauss's law and Ampere's law, focus on specific aspects of electromagnetic interactions, while Poynting's theorem provides a more comprehensive understanding of the behavior of electromagnetic waves.