Lect_28_note

Lect_28_note - Chapter 34 Electromagnetic Waves Solution of...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 34 Electromagnetic Waves
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Solution of Maxwell’s Equations z The simplest solution to the partial differential equations is a sinusoidal wave: z E = E max cos (kx – ω t) z B = B max cos (kx – ω t) 22 oo EE BB μ ε and μ ε xt ∂∂ == E c B = c = ω / k PLAY ACTIVE FIGURE
Background image of page 2
Energy z Electromagnetic waves carry energy z As they propagate through space, they can transfer that energy to objects in their path
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Poynting Vector z The rate of flow of energy in an em wave is described by a vector called the Poynting vector z The Poynting vector is defined as 1 o μ × SE B r r r
Background image of page 4
Poynting Vector 1 o μ × SE B r rr z E = E max cos (kx – ω t) z B = B max cos (kx – ω t) 1 o μ × B r E max B max cos 2 (kx – ω t)
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Poynting Vector z S represents the rate at which energy flows through a unit surface area perpendicular to the direction of the wave propagation z This is the power per unit area 1 o μ × SE B r rr E max B max cos 2 (kx – ω t)
Background image of page 6
Intensity z The wave intensity, I , is the time average of S over one cycle z The time average of cos 2 (kx - ω t) = ½
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/28/2011 for the course PHYS 011 taught by Professor Nianlin during the Fall '08 term at HKUST.

Page1 / 20

Lect_28_note - Chapter 34 Electromagnetic Waves Solution of...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online