Deck 8: The Waves

Question 1

The restoring force for ________ waves is surface tension.

Answer 1

capillary

Question 2

Waves that travel through each other tend to cancel each other out and cease to exist on the far side of the passing zone.

Answer 2

False

Question 3

A 10m long wave will have elliptical orbits in water that are 50m deep.

Answer 3

False

Question 4

More than half of the tsunami warnings issued in the last fifty years have been false alarms.

Question 5

The diameter of deep water wave orbits decrease with depth.

Question 6

The speed of a shallow water wave changes with depth, but the length of a wave does not change.

Question 7

Waves that form beneath the surface on the pycnocline are called ________ waves.

Question 8

Water particles in shallow-water waves move in ________ orbits.

Question 9

Internal waves are always standing waves.

Question 10

A ________ is a wave generated by a submarine earthquake.

Question 11

The restoring force of a capillary wave is gravity.

Question 12

Water particle orbits of shallow water waves change only their vertical dimension with depth.

Question 13

A tsunami, or seismic sea wave, travels at a speed determined by the size of the earthquake that forms it.

Question 14

When deep-water waves travel away from a storm, the longer waves move faster than the shorter waves.  This process is called sorting, or ________.

Question 15

Water particles in deep-water waves move in ________ orbits.

Question 16

Shallow-water waves will change direction as they approach shore in a process called ________.

Question 17

The equation C = gT/2n; is appropriate to determine the speed of a deep water wave.

Question 18

A tsunami is a shallow water wave.

Question 19

Wind waves in the open sea have wavelengths and speeds that are defined by the wave period.

Question 20

Storm waves in the open sea are likely to be less steep and break less often than waves in the surf zone.

Question 21

Shorter period waves travel faster than longer period waves.

Question 22

The speed of a surface gravity wave is described by the

A) wavelength times the period.
B) wave period divided by wavelength.
C) wavelength divided by wave period.
D) square of the depth.
E) Earth's gravity.

Question 23

On a standing wave, maximum vertical movement occurs at the node.

Question 24

The orbital motion of a deep water wave extends to a depth equal to

A) twice the wavelength.
B) the wave's height.
C) one-half the wavelength.
D) one-half the wave's height.
E) the seafloor depth.

Question 25

Because of dispersion the distribution of waves from a single storm changes with time and distance from the storm center.

Question 26

If a surface water wave has a wavelength of 200m and a 5-second period, its speed is

A) 4000cm/sec.
B) 400cm/sec.
C) 40cm/sec.
D) 100m/sec.
E) 10m/sec.

Question 27

The diameter of wave orbitals increases with increasing depth.

Question 28

The wave frequency is the time it takes for two subsequent wave crests to pass a location.

Question 29

A group of waves is propagated at a speed that is _______ the speed of the individual waves in deep water.

A) twice
B) the same as
C) one-half
D) one-quarter
E) one-tenth

Question 30

There are three antinodes in a double node standing wave.

Question 31

Constructive interference between waves increases the height of the resulting wave.

Question 32

The most common generating force for water waves is wind.

Question 33

Tsunami are always deep water waves.

Question 34

The maximum diameter of a water particle orbit of a deep water wave is defined by wave

A) steepness.
B) height.
C) length.
D) period.
E) speed.

Question 35

There is no vertical motion at the antinode of a standing wave.

Question 36

The period of a wave never changes.

Question 37

The restoring force of a fully developed wind wave is

A) gravity.
B) solar heat.
C) density.
D) surface tension.
E) viscosity.

Question 38

Wavelength is the distance from the crest to the trough of the same wave.

Question 39

When water depth is between L/2 and L/20, the wave speed is constant.

Question 40

Internal waves are faster and have shorter periods than most wind waves.

Question 41

The fetch of a moving storm system _______ on the side of the storm where the wind is blowing in the _______ direction as the storm is moving.

A) decreases; same
B) decreases; opposite
C) increases; same
D) increases; opposite
E) decreases; opposite and increases; same

Question 42

Waves occurring at the interface between layers of seawater and fresh water are called

A) freshwater waves.
B) interference waves.
C) density waves.
D) internal waves.
E) surface waves.

Question 43

A wave with a height of 4ft will have _______ as much energy as a 2ft wave.

A) two times
B) four times
C) six times
D) eight times
E) ten times

Question 44

When waves arrive at monitoring stations set up long distances from a storm center, which waves arrive first?

A) Long-period waves
B) Short-period waves
C) Steeper waves
D) Internal waves
E) Capillary waves

Question 45

The speed of a shallow water wave is computed from

A) C = the square root of gD.
B) C² = gL/2л.
C) C² = L/T.
D) C = L × T.
E) C = LT/g.

Question 46

Wave height of wind waves depends on

A) wavelength.
B) windspeed and duration.
C) fetch.
D) wavelength and windspeed and duration.
E) windspeed and duration and fetch.

Question 47

Swell is more regular than waves in the wind-generated area because

A) waves have been sorted by dispersion.
B) some small waves have been damped out by friction.
C) packets of swell are all at the same depth at the same time.
D) waves have been sorted by dispersion and some small waves have been damped out by friction.
E) waves have been sorted by dispersion, some small waves have been damped out by friction, and packets of swell are all at the same depth at the same time.

Question 48

In a standing wave, the positions where there is maximum vertical motion are called

A) antinodes.
B) nodes.
C) wave gaps.
D) troughs.
E) surges.

Question 49

The amplitude of a wave is about _____ the wave height.

A) one-fourth
B) one-half
C) the same as
D) twice
E) four times

Question 50

Two different wave groups with the same height travel together in the same direction. The wavelength of one group is twice as long as the wavelength of the other group. A combined wave of extra height will be produced

A) every wave.
B) every other wave.
C) every third wave.
D) every fifth wave.
E) every seventh wave.

Question 51

Water protected from direct wave influence behind a breakwater can be placed in motion by wave

A) diffraction.
B) refraction.
C) reflection.
D) All of these are correct.
E) None of these are correct.

Question 52

The average energy of a wave is determined by the wave's

A) speed.
B) length.
C) period.
D) All of these are correct.
E) None of these are correct.

Question 53

The speed of a shallow water wave varies with

A) its height.
B) the depth of the water.
C) its steepness.
D) its period.
E) its amplitude.

Question 54

In a closed basin, a single-node standing wave oscillation tends to have a wavelength that is ______ the basin length.

A) one-quarter
B) one-half
C) the same as
D) twice
E) four times

Question 55

Water particle orbits for a shallow water wave are

A) elliptic and flatten with depth.
B) elliptic and enlarge with depth.
C) circular and extend halfway to the seafloor.
D) circular at the surface and elliptical at the sea floor.
E) circular and extend to the seafloor.

Question 56

The refraction of waves tends to concentrate wave energy ______ and disperse energy _____.

A) in bays; on headlands
B) on headlands; in bays
C) along coasts; behind breakwaters
D) along coasts; on headlands
E) along coasts; in bays

Question 57

If a wave is a capillary wave, the force that causes the water to return to its undisturbed level is

A) gravity.
B) wind.
C) seismic forces.
D) surface tension.
E) All of these are correct.

Question 58

Waves moving against a current will

A) increase their height.
B) decrease their speed.
C) shorten their wavelength.
D) All of these are correct.
E) None of these are correct.

Question 59

The average energy of a wave is related to the square of its

A) height.
B) wave length.
C) period.
D) speed.
E) All of these are correct.

Question 60

Water transported shoreward in the surf zone is returned seaward by

A) shallow water waves.
B) reflected waves.
C) refracted waves.
D) rip currents.
E) internal waves.

Question 61

A long wave with a period of about fifteen minutes will travel across the oceans at a speed of approximately

A) 2m/sec.
B) 20m/sec.
C) 200m/sec.
D) 2km/sec.
E) 20km/sec.

Question 62

If the wave height of 1500 waves is recorded, significant wave height will be the average of the highest

A) 15.
B) 150.
C) 300.
D) 500.
E) 750.

Question 63

A water wave reaches an unstable breaking point when the steepness ratio, H/L, reaches

A) 1:10.
B) 1:8.
C) 1:7.
D) 1:5.
E) 1:2.

Question 64

Speed of shallow water waves is controlled by

A) height.
B) steepness.
C) celerity.
D) wavelength.
E) water depth.

Question 65

Typical wavelength of a tsunami is

A) 1 to 2m.
B) 10 to 20m.
C) 100 to 200m.
D) 100 to 200km.
E) 1000 to 2000km.

Question 66

A wave breaks when

A) h/L = 1/7.
B) L/h = 1/7.
C) h = 3m.
D) L = 3m.
E) L/h = 3/7.

Question 67

Wave refraction results in

A) wave energy concentrating in bays.
B) wave energy decreasing in bays.
C) wave energy focusing on headlands.
D) wave energy concentrating in bays and wave energy focusing on headlands.
E) wave energy decreasing in bays and wave energy focusing on headlands.