1. All sound waves are .A. longitudinal wavesB. transverse wavesC. electromagnetic wavesD. standing wavesE. loud

2. The speed of sound depends on .A. the temperature of the mediumB. the density of the mediumC. the type of mediumD. how well the medium will transfer energyE. All of the above

3. A sonar device can use echoes of ultrasound under water to find .A. the speed of soundB. the depth of the waterC. the temperature of the waterD. underwater objectsE. both B and D

4. During a thunderstorm, you see lightning before you hear thunder because . A. the thunder occurs after the lightningB. the thunder is farther away than the lightningC. sound travels faster than lightD. light travels faster than soundE. light travels in the form of a wave and sound does not

ReviewReviewSound Pitch Loudness EchoResonance

Electromagnetic SpectrumElectromagnetic Spectrum

EMS“light” from the sunMost of the EMS can not be

seen

Electromagnetic SpectrumElectromagnetic Spectrum

Electromagnetic waves Do not require a medium Transverse waves

Radio WavesRadio WavesLongest

wavelengthsLowest energy AM, FM, TV,

Shortwave

Can’t see

these!

Radio WavesRadio WavesKeyless entryGarage door openers

MicrowavesMicrowavesHigher energy than radio

wavesShorter wavelength

Can’t see

these!

MicrowavesMicrowaves

Cooking

Can’t see

these!

Cell PhonesCell PhonesUse wavelengths/frequencies

right on the dividing line between radio and micro waves

In half-duplex radio, both transmitters use the same frequency. Only one person can talk at a time

In full-duplex radio, the two transmitters use different frequencies, so both people can talk at the same time.Cell phones are full-duplex.