chapter 7: waves

Question 1

Beats measure

Answer 1

the difference between two frequencies

Question 2

Waves tend to bend in to the side

Answer 2

with slower wave velocity

Question 3

The fastest earthquake wave is the

Answer 3

P wave

Question 4

The slowest earthquake wave is the

Answer 4

L wave

Question 5

An octave refers to two frequencies that differ by a factor of

Answer 5

2

Question 6

When two different waves pass through an opening of the same size, which one will spread more?

Answer 6

larger wavelength

Question 7

The fastest sound wave is:

Answer 7

they all travel at the same speed

Question 8

You can measure the distance to the epicenter by measuring

Answer 8

the time between the P & S waves

Question 9

Sound travels fastest in

Answer 9

rock

Question 10

When an opening gets smaller, a wave that passes through it

Answer 10

spreads more

Question 11

The very center of the Earth is

Answer 11

solid iron

Question 12

Which kind of earthquake is purely longitudinal?

Answer 12

P wave

Question 13

Which of the following statements about earthquakes is true?

Answer 13

P waves are the fastest, and L waves cause the most destruction.

Question 14

The L wave is often the most damaging because

Answer 14

it stays on the surface, so it doesn’t spread out very much

Question 15

An earthquake wave does its worst damage when it reaches an area that

Answer 15

slows it down

Question 16

Landfill is dangerous because

Answer 16

the amplitude of the earthquake increases

Question 17

Where there is an atmospheric inversion, sound tends to

Answer 17

become focused

Question 18

The ocean sound channel

Answer 18

is very quiet

Question 19

Sound tends to bend toward the side with

Answer 19

colder air

Question 20

The same note is played on two pianos. Beats are heard once per second. From this, we deduce that

Answer 20

at least one of the pianos is out of tune (the notes are the wrong frequency)

Question 21

We know that the inner part of the Earth is liquid because

Answer 21

no S waves move across it

Question 22

A magnitude 9 earthquake, compared to a magnitude 8 earthquake

Answer 22

has 10 to 30 times more energy

Question 23

You feel the tremors of an earthquake. Ten seconds later, you feel another shaking. The distance to the epicenter is about:

Answer 23

50 miles

Question 24

If we double the frequency of sound, the wavelength is

Answer 24

halved

Question 25

Beats demonstrate that

Answer 25

sound is a wave

Question 26

The velocity of sound is approximately

Answer 26

1000 feet per second

Question 27

The speed of sound in air

Answer 27

increases as air temperature increases

Question 28

Sound waves are

Answer 28

compressional (longitudinal)

Question 29

On a typical day, sound emitted near the ground tends to bend

Answer 29

upwards toward the sky

Question 30

You are more likely to hear distant sounds when

Answer 30

the air near the ground is cool and the air above it is warm

Question 31

Because of evaporation, the air above the surface of a lake become cool. Sound in the air above the lake will tend to

Answer 31

bend downward toward the surface

Question 32

To have a sound channel, there must be

Answer 32

a minimum in the velocity of the sound

Question 33

SOFAR took advantage of

Answer 33

the sound channel in the ocean

Question 34

Water waves are

Answer 34

both transverse and longitudinal

Question 35

The sound channel in the ocean carries sound along a long distance because

Answer 35

the sound doesn't spread out in the up or down directions

Question 36

As you travel deeper into the ocean, the water temperature

Answer 36

decreases with depth

Question 37

A pianist plays two keys: middle C, and the C above middle C (i.e., an octave higher). The speed of sound for the higher frequency, compared to that for the lower frequency, is

Answer 37

the same

Question 38

As you move to a higher altitude, the temperature of the air

Answer 38

first gets cooler, then warmer

Question 39

The atmospheric sound channel would not exist, if not for

Answer 39

UV light

Question 40

The ozone layer is created by

Answer 40

sunlight

Question 41

SOSUS refers to

Answer 41

a system for detecting submarines

Question 42

Which of the following statements was true about Project Mogul?

Answer 42

It was concerned with the atmosphere

Question 43

According to this text, the flying disks that crashed near Roswell were

Answer 43

microphones

Question 44

Very long wavelength water waves

Answer 44

travel faster than short ones

Question 45

Whales and fiber optics both make use of what principle?

Answer 45

Huygens

Question 46

When an earthquake at sea starts a tsunami or tidal wave, the initial height is relatively small. What accounts for the towering wave that breaks near the shore?

Answer 46

the waves move slower

Question 47

A water wave has a wavelength of 10 meters and frequency of 2 cycles/sec. Its velocity is

Answer 47

20 meters per second

Question 48

The sound from a passing car sounds like a high pitch, but as it passes, it gets lower. That's an example of

Answer 48

the Doppler shift

Question 49

Thunderclouds tend to rise until

Answer 49

they reach air that is warmer than they are

Question 50

The atmospheric sound channel is created because of

Answer 50

UV light

Question 51

In the daytime, sound tends to

Answer 51

bend upward

Question 52

Most damage from an earthquake usually comes from the

Answer 52

L wave

Question 53

For sound waves, low-frequency waves travel

Answer 53

the same speed as high frequency

Question 54

The piano note A above middle C is 440 Hz. The next higher A has a frequency

Answer 54

880