EM Waves

Type of Wave:  Transverse wave

Wave speed:  fastest in a vacuum (empty space)->gases->liquids->solids (because molecules slows down the light wave)

Speed of light is 3 x 10^8 m/s

e-m spectrum:  (least energy)radio-microwave-IR-visible-UV-x rays-gamma (most energy)

our eyes assume that light comes directly from an object in a straight line

Doppler Effect

- Doppler Effect is the apparent change in frequency due to a moving source, listener, or both

- compressions bunch up in front, and spread apart in back.

- if the source and listener are moving closer together:  frequency will increase (for sound pitch get higher)

- if the source and listener are getting farther apart:  frequency will decrease (for sound pitch gets lower)

- the frequency will change more as the relative speeds increase

Sound Waves

Parts of a Sound Wave

- sound is longitudinal wave

- longitudinal waves has compressions (crest) and rarefactions

- sound travels faster and better through:  solids->liquids->gases

(this is because molecules have less distance to travel )

- sound travels faster in high temperatures and slower in low temperatures

- frequency corresponds to pitch (lower frequency means lower pitch)

- speed of sound is constant (for air at room temperature it is 340 m/s)

- use v = (delta) x/(delta) t  or v = (lamda) f