University:
Santa Fe College
Course:
ETS 2527C | Electromechanical Components and Mechanisms
Academic year:

2024
Views:

499

Pages:

5
Author:

Jabin F.

Heading: # Poynting vector (S) associated with waves. Definition: It is defined as energy per unit area per unit time associated with the wave. Equation for Poynting Vector: S = (E x H) = (E x B) / μ₀ Units: J/m²s or W/m² Direction of Poynting Vector: Represents the direction of energy flow. Relationship Between Phase Velocity and Group Velocity: Phase Velocity (vp): Direction of wave propagation. Group Velocity (vg): Direction of energy flow. Equation for Energy Density (u): u = (E² + B²) / 2μ₀ Relationship Between Poynting Vector and Energy Density: S = c * u Derivation of Poynting Vector: Equation 1: S = ε₀cE² Equation 2: S = ε₀cε² = ε₀c(E² + B²/μ₀) Equation 3: uem = ε₀E² + B²/2μ₀ (where uem is the electromagnetic energy density) Equation 4: S = cuem Interpretation: The Poynting vector (S) is equal to the electromagnetic energy density (uem) multiplied by the speed of light (c). This shows that electromagnetic energy is carried with the speed of light in the z-direction. Units of Poynting Vector: J/m²s or W/m² Conclusion: The Poynting vector represents the "power per unit area" associated with an electromagnetic wave.