Sound Waves

Question 1

What are the three different levels of sound waves?

Answer 1

• infrasonic
• audible
• ultrasonic

Question 2

What is the speed of sound at 0ºC?

Answer 2

331 m/s

Question 3

What is an open pipe?

Answer 3

• Both ends of a pipe are open

Question 4

What is a closed pipe?

Answer 4

• One end of the pipe is open

Question 5

What is the speed of sound at room temperature?

Answer 5

340 m/s

Question 6

What harmonics are shown in open pipes?

Answer 6

All harmonics

Question 7

What harmonics are shown in closed pipes?

Answer 7

Only odd-numbered harmonics

Question 8

Superimposed waves will always have the frequency of which harmonic?

Answer 8

The first

Question 9

What does a tuning fork do?

Answer 9

Produces the fundamental frequency

Question 10

The first harmonic is called the fundamental. What are the other harmonics called?

Answer 10

Overtones

Question 11

What does the cochlea do? What is it?

Answer 11

It is a snail-shaped organ filled with liquid that uses standing waves to help hear

Question 12

What is the average intensity of a sound wave?

Answer 12

• 1/A * ∆E / ∆t
• P/A
  A = area
  P = Power
  ∆E / ∆t = Rate of energy flow

Question 13

What is the energy propagated for spherical waves?

Answer 13

I = P(av) / A
I = P(av) / 4πr^2

Question 14

What relationship do spherical waves have?

Answer 14

• Inverse square relationship
• 1 / r^2

Question 15

How do you find he intensity level of a sound?

Answer 15

ß = 10log(I/I(0))
I(o) = Threshold of hearing

Question 16

What is the threshold of hearing?

Answer 16

1 x 10^-12 W/m^2

Question 17

An increase in 10 dB is equal to how many times the loudness?

Answer 17

2 times

Question 18

What is sound measured in?

Answer 18

dB

Question 19

The direction of energy flow for sound waves is ____ to the surface at ___ point.

Answer 19

Perpendicular; every

Question 20

What is a beat?

Answer 20

A pulsing change in loudness

Question 21

How do you find the beat frequency? What does it tell you?

Answer 21

f(beat) = |f(1) - f(2) |
Tells us beats per second

Question 22

What is a compression?

Answer 22

A region where air particles are pushed together
- High pressure and density

Question 23

What is a rarefaction?

Answer 23

A region where air particles are pushed far apart
- Low pressure and density

Question 24

What is the doppler effect?

Answer 24

• When an object goes nears you, waves get bunched up and you experience a higher pitch
• When an object goes away from you, waves get further apart and you experience a lower pitch

Question 25

What is an infrasound? What are some examples?

Answer 25

- Below audible levels - Earthquakes, volcanos, etc.

Question 26

What is an ultrasound?

Answer 26

- Above audible levels

Question 27

What are the ossicles?

Answer 27

- Three tiny bones in ears - Amplify vibrations from eardrum and transport them inner ear

Question 28

An increase in 10 dB is equal to how many times the intensity?

Answer 28

10 times

Question 29

An increase in a sound wave's amplitude will result in the increase of what?

Answer 29

Increase in loudness

Question 30

An increase of a sound wave's wavelength will result in what change of the frequency?

Answer 30

Decrease

Question 31

As the frequency of a sound increases, what happens to the pitch?

Answer 31

Increases