Chapter 8 - Sound

Question 1

How do ultrasonic waves break apart plaque formations?

Answer 1

Plaque formations vibrate at a resonant frequency equal to the frequency of the ultrasonic waves.

Question 2

Sound waves travel fastest through…

Answer 2

Solids - fastest
Liquids
Gasses - slowest

Question 3

Define a hearing range

Answer 3

The difference between highest and lowest frequencies

Question 4

Sound waves travel by causing the medium they travel in to…

Answer 4

Vibrate in the same direction which the wave is travelling

Question 5

When a sound wave moves toward a stationary observer what do they hear in relation to what was emitted?

Answer 5

They hear a HIGHER frequency than what was emitted.

Question 6

Sound pressure is measured using 2 unit types. What are they and what are there equations?

Answer 6

Decibels (dB) = 10 log (i/io)
Pascals = 1 N / m^2

• where i is sound intensity (i = power/area)

Question 7

What is the equation for frequency?

Answer 7

F(o) = Fs (V +- Vo)/(V +- Vs)

Where
Fo is frequency of observer
Fs is frequency of source
V is speed

*If the sound is travelling TOWARDS the observer +Vo and -Vs

Question 8

Define and give example of Doppler effect

Answer 8

Observed frequency caused by motion of the observer and the source.

If they become
FURTHER APART = LONG wavelength = LOW FREQUENCY

If they become
CLOSER = SHORT wavelength = HIGH frequency

Question 9

Define

Intensity
Frequency
Wave form

What is the influence of temperature on velocity of sound?

How is the absolute difference of frequencies defined?

Answer 9

Intensity = loudness
Frequency = pitch
Quality = waveform 

Increased temp = increased velocity of sound

Number of beats per second = absolute difference of frequencies