Chapter 19 Physics Review Q's

Front 1

How does a physicist usually define sound?

Back 1

A form of energy that exists whether or not it is heard

Front 2

What is the source of all sounds?

Back 2

the vibration of material objects

Front 3

What is the relationship between frequency and pitch?

Back 3

We describe our subjective impression about the frequency of sound by the word pitch. A high-pitched sound like that from a piccolo has a high frequency vibration and a low foghorn pitch has a low frequency vibration

Front 4

What is the average range of a youn person's hearing?

Back 4

range between 20 to 20,000 hertz

Front 5

Distinguish between infrasonic and ultrasonic sound waves.

Back 5

Sound waves with frequencies below 20 hertz are infrasonic, and those with frequencies above 20,000 hertz are ultrasonic

Front 6

distinguish between a compression and a rarefaction

Back 6

compression- is molecules pushing up against each other until they push out, like the pressure of opening a door in a room that eventually pushes air out of the opposing window. While rarefaction occurs when closing a door, as it has removed pressure in the room, and a zone of low pressure is is called rarefied, making other molecules of air move into the vacuum instead of being pushed.

Front 7

do compressions and rarefactions travel in the same or opposite directions in a wave? cite evidence to support your answer.

Back 7

The same, as the wave either pushes or pulls

Front 8

How does the paper cone of a radio loudpeaker emit sound?

Back 8

The radio loudspeaker is a paper conet hat vibrates in a rhythm whith an electrical signal. Air molecules next to the vibrating cone of the speaker are themselves set into vibration. This air in turn vibrates against neighboring particles, which in turn do the same, and so on. As a result, rhythmic patterns of compressed and rarefied air emanate from the loudspeaker, showering the whole room with undulating motions. The resulting vibrating air sets your eardrum into vibration , which in turn sends cascades of rhythmic electrical impulses along the cochlear nerve ad into the brain. And you listen to the sound of music.

Front 9

Relative to solids and liquids, how does air rank as a conductor of sound?

Back 9

Air is a poor conductor of sound relative to solids and liquids.

Front 10

Why will sound not travel in a vacuum?

Back 10

There is no material to vibrate

Front 11

What factors does the speed of sound depend upon?

Back 11

wind conditions, temperature, and humidity

Front 12

What is the speed of sound in dry air at 0 degrees celcius?

Back 12

330 meters per second

Front 13

Does sound travel faster in warm air than in cold air? defend your answer

Back 13

Warm air because the molecules are moving faster

Front 14

How does the speed of sound in water compare with the speed of sound in air? How does the speed in steel compare with the speed in air

Back 14

sound travels 4 times faster in water than in air and 15 times faster in steel than in air`

Front 15

what is the cause of refraction?

Back 15

uneven winds or when the air sound is traveling through is of uneven temperatures

Front 16

Does sound tend to bend upward or downward when its speed is less near the ground?

Back 16

IT bends Away from the ground

Front 17

Why does sound sometimes refract under water?

Back 17

because the speed of sound varies with temperature

Front 18

There is a difference between the way we passively see our surroundings in daylight and the way we actively probe our surroundings with a searchlight in darkness. Which of these ways of perceiving our surroundings is more like the way a dolphin perceives its environment?

Back 18

More like in the nighttime with a searchlight as they locate and identify everything with sound

Front 19

Give at least two factors that determine the natural frequency of an object.

Back 19

elasticity and shape of teh object

Front 20

does a blob of putty have a natural frequence? explain

Back 20

Yes because everything even atoms have a springiness and virbate at one or more natural frequencies

Front 21

Distinguish between forced vibrations and resonance?

Back 21

When the frequency of forced vibrations on an object matches the objects natural frequency there is a dramatic increase in amplitude

Front 22

What is required to make an object resonate?

Back 22

it needs a force to pull it back to its starting position and enough energy to keep it vibrating

Front 23

When you listen to a radio, why do you hear only one station at a time instead of hearing all stations at once?

Back 23

When you tune your radio set you are adjusting the natural frequency of the electronics in the set to match one of the many surrounding signals. The set then resonates to one station at a time istead of playing all stations at once

Front 24

Why do troops "break step" when crossing a bridge?

Back 24

So as not to create a resonance that matches that of the bridges natural frequency and making it collapse.

Front 25

What physical phenomenon underlies the production of beats?

Back 25

When two tones of slightly different frequency are sounded together, a fluctuation in the loudness of the combined sounds is heard, loud then faint then loud ..etc.

Front 26

What beat frequency will be heard when a 370-Hz and a 374- Hz tuning fork are sounded together?

Back 26

4 hertz ( i think)

Front 27

How is the phenomenon of beats useful for tuning musical instruments?

Back 27

To tune a piano, they listen for the beats produced between a standard tuning fork and those of a particular string on the piano. When the frequencies are identical, the beats disappear.

Front 28

How does a radio wave differ from a sound wave?

Back 28

radio waves are low frequency light waves they have a much higher frequency than sound waves.

Front 29

Distinguish between a carrier wave and a sound wave.

Back 29

the carrier wave is an electromagnetic wave and can have lower frequency sound waves piggy back on it

Front 30

Distinguish between AM and FM

Back 30

Am (amplitude modulation) broadcasts a range of 535 to 1605 kilohertz while FM (frequency modulation) broadcast in the higher frequency range of 88-108 megahertz

Front 31

How is tuning a radio like adjusting a pair of tuning forks for resonance?

Back 31

because it it is like adjusting moveable masses on the prongs of a tuning fork to make it resonate to the sound produced by another fork. In choosing a radio station you adjust the frequency of an electrical circuit inside the radio receiver to match and resonate with the frequency at the station you want. Sorting out one carrier wave from many .