Difference between revisions of "Main Page/PHYS 3220/Speed of Light"

From Physics Wiki
Jump to navigation Jump to search
Line 13: Line 13:
 
</p>
 
</p>
 
</td></table>
 
</td></table>
 +
<p>is called the phase of the plane wave. A point on the wave having a constant phase (e.g. the peak of a sine wave) moves at a velocity determined by setting the time derivative of the constant phase equal to zero</p>

Revision as of 15:14, 18 July 2011

Introduction

Light can be described as a periodic electromagnetic plane wave which carries energy in the form of an electromagnetic field. The electric and magnetic components can be written as:

C-eqn1.png

C-eqn1b.png

This represents a monochromatic (single-frequency) beam travelling in the + z direction having a wavelength λ and frequency v (related by λ ν = c). The angle

C-eqn2.png

is called the phase of the plane wave. A point on the wave having a constant phase (e.g. the peak of a sine wave) moves at a velocity determined by setting the time derivative of the constant phase equal to zero