ᴘʀᴏᴘᴇʀᴛɪᴇs ᴏғ ʟɪɢʜᴛ

                  5 - 7 

╓═══════☆═══════╖

                Waves

╙═══════☆═══════╜

beam of light produced by laser. sound generated

by thunderclap, ripples in ponds are all waves

wave: motion of disturbance between two points

classified as transverse or longitudinal

transverse: oscillations perpendicular to direction

that the wave travels, ex: light

longitudinal: oscillations parallel to direction the wave

travels ex: sound

all waves originate from vibrations which initiate series

of collisions between air molecules

waves transport energy but not mass

╓═══════☆═══════╖

        Waves Properties

╙═══════☆═══════╜

amplitude:  maximum displacement from equilibrium

refers to maximum magnitude of electric & magnetic

fields for electromagnetic waves

wavelength (λ): defined as distance between two 

consecutive corresponding points on wave

frequency (f): number of oscillations in a certain time

standard unit is hertz (Hz) = 1 oscillation/sec

period (T): amount of time between oscillations

T = 1/f

wave speed (v): related to both frequency & wavelength

v = distance/time =  λ/T

v = fλ

higher frequency = shorter wavelength

╓═══════☆═══════╖

         Electromagnetic

                Waves

╙═══════☆═══════╜

light is an electromagnetic wave, which is a wave made 

up of electric and magnetic fields that oscillate

both fields are perpendicular to each other

classified as transverse

do not need physical medium to move through, unlike

mechanical waves (such as sound), can travel through

vacuum of space

caused by vibration of charged particles (protons & electrons)

charged particles surrounded by electric field that exerts 

force on other charged charged particles

when charged particle accelerates, fluctuations in electric

field cause self perpetuating "pulse"

in early 1860s, Scottish physicist James Clerk Maxwell

derived system of equations for describe behavior of 

electric & magnetic fields

in paper presented to Royal Society in 1864, Maxwell use 

these equations to predict existence of electromagnetic waves

when sinusoidally-oscillating charged particle creates

oscillating electric field, oscillating perpendicular magnetic

field also created 

these two mutually perpendicular oscillating fields form

an electromagnetic wave