Question 1

Beats measure:

Accepted Answer

The difference between two frequencies.

Question 2

Waves tend to bend in to the side:

Accepted Answer

With slower wave velocity.

Question 3

The fastest earthquake wave is the:

Accepted Answer

P wave.

Question 4

The slowest earthquake wave is the:

Accepted Answer

L wave.

Question 5

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

Accepted Answer

2.

Question 6

The fastest sound wave is:

Accepted Answer

They all travel at the same speed.

Question 7

You can measure the distance to the epicenter by measuring:

Accepted Answer

The time between the P and S waves.

Question 8

Sound travels fastest in:

Accepted Answer

Rock.

Question 9

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

Accepted Answer

Spreads more.

Question 10

The very center of the Earth is:

Accepted Answer

Liquid iron.

Question 11

What kind of earthquake is purely longitudinal?

Accepted Answer

P wave.

Question 12

Which of the following statements about earthquakes is true?

Accepted Answer

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

Question 13

The L wave is often the most damaging because:

Accepted Answer

It stays on the surface, so it doesn't spread out very much.

Question 14

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

Accepted Answer

Slows it down.

Question 15

Landfill is dangerous because:

Accepted Answer

The amplitude of the earthquake increases.

Question 16

When there is an atmospheric inversion, sound tends to:

Accepted Answer

Bend downward.

Question 17

The ocean sound channel:

Accepted Answer

Is very quiet.

Question 18

Sound tends to bend toward the side with:

Accepted Answer

Colder air.

Question 19

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

Accepted Answer

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

Question 20

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

Accepted Answer

No S waves move across it.

Question 21

A magnitude 9 earthquake, compared to a magnitude 8 earthquake:

Accepted Answer

Has 10 to 30 times the energy.

Question 22

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

Accepted Answer

50 miles.

Question 23

If we double the frequency of sound, the wavelength is:

Accepted Answer

Halved.

Question 24

Beats demonstrate that:

Accepted Answer

Sound is a wave.

Question 25

The velocity of sound is approximately:

Accepted Answer

1000 feet per second.

Question 26

The speed of sound in air:

Accepted Answer

Increases as temperature increases.

Question 27

Sounds waves are:

Accepted Answer

Compressional (longitudinal)

Question 28

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

Accepted Answer

Upward, toward the sky.

Question 29

You are more likely to hear distant sounds when:

Accepted Answer

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

Question 30

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

Accepted Answer

Bend downward toward the surface.

Question 31

To have a sound channel, there must be:

Accepted Answer

An increase in the velocity with depth.

Question 32

SOFAR took advantage of:

Accepted Answer

The sound channel in the ocean.

Question 33

Water waves are:

Accepted Answer

Both transverse and longitudinal.

Question 34

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

Accepted Answer

The sound doesn't spread in the up or down directions.

Question 35

As you travel deeper into the ocean, the water temperature:

Accepted Answer

Decreases with depth.

Question 36

A pianist plays 2 keys: middle C, and the C above middle C (i.e., an octave higher.) The SPEED OF SOUND for the higher frequency, comopared to that for the lower frequency, is:

Accepted Answer

The same.

Question 37

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

Accepted Answer

First gets cooler, then warmer.

Question 38

The atmospheric sound channel would not exist, if not for:

Accepted Answer

Ultraviolet light.

Question 39

The ozone layer is created by:

Accepted Answer

Sunlight.

Question 40

SOSUS refers to:

Accepted Answer

A system for detecting submarines.

Question 41

Which of the following statements was true about Project Mogul?

Accepted Answer

It was concerned with the atmosphere.

Question 42

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

Accepted Answer

Microphones.

Question 43

Very long wavelength water waves:

Accepted Answer

Travel faster than short ones.

Question 44

Whales and fiber optics both make use of what principle?

Accepted Answer

Huygens.

Question 45

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?

Accepted Answer

The wave moves slower.

Question 46

A water wave has a wavelength of 10 meters and a frequency of 2 cycles/sec. It's velocity is:

Accepted Answer

20 meters per second.

Question 47

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

Accepted Answer

The Doppler Shift

Question 48

Thunderclouds tend to rise until:

Accepted Answer

They reach air that is warmer than they are.

Question 49

The atmospheric sound channel is created because of:

Accepted Answer

Ultraviolet light.

Question 50

In the daytime, sound tends to:

Accepted Answer

Bend upward.

Question 51

Most damage from an earthquake usually comes from the:

Accepted Answer

L wave.

Question 52

For sound waves, low-frequency waves travel:

Accepted Answer

At the same speed as high frequency.

Question 53

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

Accepted Answer

880 Hz.

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PHY1020-Chapter 7