Chapter 20: Sound

Question 1

Sound is a variation of

Answer 1

The pressure of a medium

Question 2

Sound is a typically of

Answer 2

Air

Question 3

Sound propagates as a

Answer 3

Longitudinal pressure wave

Question 4

Sound travel at a speed characteristics of

Answer 4

The medium in which it propagates

Question 5

Sound is our ear are devices which

Answer 5

Detect sound

Question 6

Sound is a form of

Answer 6

Energy that exist whether or not it is heard

Question 7

Most sounds are waves produced by

Answer 7

The vibration of matter

Question 8

The vibrating material then sends a disturbance through the surrounding medium, usually air, in the form of

Answer 8

Longitudinal sounds waves

Question 9

Under ordinary condition, the frequencies of the vibrating source and sound waves are

Answer 9

The same

Question 10

The subjective impression about the frequency of sound is called

Answer 10

Pitch

Question 11

The ear of a young person can normally hear pitches corresponding to the range of frequencies between about

Answer 11

20 and 20,000 Hertz

Question 12

Sound waves with frequencies below 20 Hertz are

Answer 12

Infrasonic (frequency too low for human hearing)

Question 13

Sound waves with frequencies above 20,000 hertz are called

Answer 13

Ultrasonic (frequency too high for human hearing)

Question 14

Human cannot hearing the two different types of sounds, what was that?

Answer 14

Infrasonic and ultrasonic sound

Question 15

Sound waves are

Answer 15

Vibrations made of compressions and rarefraction

Question 16

Sound waves are (2)

Answer 16

Longitudinal waves

Question 17

Sound wave requires

Answer 17

A medium

Question 18

Sound wave travels through

Answer 18

Solids, liquids, and gases

Question 19

The wavelength of sound were the distance between

Answer 19

Successive compressions or rarefactions and both of them travel at the same wave speed

Question 20

Medium that transmit

Answer 20

Sound

Question 21

Any elastic substance - solid, liquid, gas, or plasma can

Answer 21

Transmit sound

Question 22

In elastic liquids and solids, the atoms are relatively

Answer 22

Close together, respond quickly to one another’s motions and transmit energy with little loss

Question 23

Sound wave about 4 times faster in water than in air and about

Answer 23

15 times faster in steel than in air

Question 24

Speed of sound in air depends on

Answer 24

Wind conditions, temperature, humidity

Question 25

Speed in dry air at 0 degree Celsius is about

Answer 25

330 m/s (738 mph) and in water it is vapor slightly faster and in warm air faster than cold air

Question 26

Each degree rise in temperaure above (0 degree Celsius), speed of air increases by

Answer 26

(0.6 m/s) or 0.6 T

Question 27

Reflection

Answer 27

Process in which sound encountering a surface is returned

Question 28

Reflection often called an

Answer 28

Echo

Question 29

Multiple reflection called

Answer 29

Reverberations

Question 30

Reflection of the sound reflects from a

Answer 30

Smooth surface the same way that light does

Question 31

Angle of incidence equals to

Answer 31

Angle of reflection

Question 32

If the reflective surface are too

Answer 32

Absorbent, the sound level will be low and the room will sound dull and lifeless

Question 33

Reverberations are best heard when you sing in a room with

Answer 33

Hard-surfaced walls

Question 34

Accoustic

Answer 34

Study of properties of sound

Question 35

Some have reflectors to

Answer 35

Direct sound which also reflect light so what you see is what you hear

Question 36

Refraction

Answer 36

Bending of waves caused by changes in speed affected by wind variations and temperature variations

Question 37

Sound does not always travel in

Answer 37

Straight line paths

Question 38

Sound bends from warmer (less dense) air to

Answer 38

Cooler (denser) air

Question 39

When air near the ground on a warm day is warmed more than the air above, sound tends to bend

Answer 39

Upward

Question 40

In the evening, when air directly above a pond is cooler than air above, sound across a pond tends to bend

Answer 40

Downward

Question 41

Ultrasound

Answer 41

Multiple reflection and refractions of high frequency sound waves

Question 42

Ultrasound devices sends

Answer 42

High-frequency sounds into the body

Question 43

Wave reflects more strongly from the exterior of the organs, producing an

Answer 43

Image of the organs

Question 44

Ultrasound used instead of X-ray by physician to

Answer 44

See the interior of the body

Question 45

Dolphin emit ultrasonic waves to enable them to

Answer 45

Locate object in their environment

Question 46

Forced vibration establishing in an object by

Answer 46

A vibrating force

Question 47

If we hold a tuning fork against a table after striking it, the sound is

Answer 47

Louder because the table is forced to vibrate, and with its larger surface area, the table sets more air in motion

Question 48

A frequency or a set of frequencies at which an object preferentially vibrates determined by

Answer 48

Elasticity of the object and the shape of it

Question 49

A phenomenon in which the frequency of forced vibrations on an object matches

Answer 49

The object's natural frequency

Question 50

Interference is a property of

Answer 50

All waves and wave motion

Question 51

Interference: Superposition of waves that may

Answer 51

Either reinforce (add) or cancel each other (subtract)

Question 52

Two patterns of interference

Answer 52

1) Constructive interference 2) Destructive interference

Question 53

Constructive interference increased amplitude when

Answer 53

The crest of one wave overlaps the crest of another wave

Question 54

Destructive interference reduced amplitude when

Answer 54

The crest of one wave overlaps the trough of another wave

Question 55

Beat is a

Answer 55

Periodic variations in the loudness of sound due to interference

Question 56

Beat occur with any kind of

Answer 56

Wave

Question 57

Beat provide a comparison of

Answer 57

Frequencies

Question 58

The interference of two sound sources of slightly different frequencies produces

Answer 58

Beats