Formula of Poynting
Formally, Poynting vector is the cross product of electric field(E) and magnetic field(B), respectively. Note that the order in which these terms are written is very necessary.
Poynting vector= cross product of electric field and magnetic field
S=E×B/ μ
S is Poynting Vector
E is Electric Field
B is Magnetic Field
Here it is important to note that the Poynting vector represents the direction and magnitude of energy flow. The electric field is the field that causes a charged particle to experience the force in an electromagnetic field. The magnetic field is responsible for all the the magnetic properties of the electromagnetic wave.
To calculate the magnitude of Poynting vector ,we can further represent cross product in terms of sin(θ) as
|S| = 1/μ0(|E| * |B| * sin(θ))
|E| is magnitude of the electric field
|B| is magnitude of the magnetic field
θ is angle between the two fields.
μ0= vacuum permeability = 1.257 x 10-6 henry/ meter
Poynting Vector
Poynting Vector as the name suggests is a quantity that has both magnitude and direction. In the electrical industry, whilst dealing with electromagnetic waves, we often have to come across some tools that can help us analyze these waves. If we think about how electromagnetic waves travel, we realize that we need a term to define the energy flux density of these waves and this is represented by Poynting Vector. Basically, the Poynting vector represents power per unit area. It generally is defined as the cross-product of an electric field and magnetic field, giving us the direction of energy flux which is in the direction of wave propagation. In this article, we will learn about Poynting Vector, its meaning, and its physical Interpretation. We will also discuss the components used in the formula of the Poynting vector. Later we will discuss some advantages and disadvantages of the Poynting vector and how are they put into use. We will conclude the article with some Frequently Asked Questions.
Table of Content
- What is Poynting Vector?
- Physical Interpretation of Poynting Vector
- Formula of Poynting
- Advantages of Poynting Vector
- Disadvantages of Poynting Vector
- Vector Applications of Poynting Vector
- Solved Examples
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