Navigation Flashcards
(137 cards)
1
Q
Why are radar waves restricted in recording the range of low-lying objects?
A) Due to interference from other vessels
B) Because of the curvature of the Earth, limiting the radar horizon
C) Because radar waves cannot penetrate water
D) Due to limitations in the radar system’s power
A
B) Because of the curvature of the Earth, limiting the radar horizon
2
Q
What factors determine the range of the radar horizon?
A) The frequency of the radar wave and the speed of the vessel
B) The type of radar system and the material of the radar antenna
C) The height of the antenna and the curvature of the Earth
D) The distance to the nearest coastline and the presence of other vessels
A
C) The height of the antenna and the curvature of the Earth
3
Q
What distinguishes diffraction from refraction in terms of radar wave behavior?
A) Diffraction is caused by atmospheric conditions, while refraction is a property of electromagnetic waves.
B) Diffraction results from the curvature of the Earth, while refraction is due to the height of the radar antenna.
C) Diffraction is a property of electromagnetic waves, while refraction is influenced by atmospheric conditions.
D) Diffraction occurs when radar waves bounce off surfaces, while refraction occurs when radar waves bend due to the curvature of the Earth.
A
C) Diffraction is a property of electromagnetic waves, while refraction is influenced by atmospheric conditions
4
Q
What is the definition of diffraction?
A) Diffraction is the bending of a wave as it passes through a medium.
B) Diffraction is the reflection of a wave from a surface.
C) Diffraction is the absorption of a wave by a material.
D) Diffraction is the bending of a wave as it passes an obstruction.
A
D) Diffraction is the bending of a wave as it passes an obstruction.
5
Q
How does refraction affect the detection range of objects?
A) Refraction increases the detection range of objects.
B) Refraction decreases the detection range of objects.
C) Refraction has no effect on the detection range of objects.
D) Refraction may alter the detection range of objects depending on atmospheric conditions.
A
D) Refraction may alter the detection range of objects depending on atmospheric conditions.
6
Q
What relationship between the radar horizon and the geometric horizon holds true in the absence of refraction effects?
A) They are always equal regardless of atmospheric conditions.
B) The radar horizon is always greater than the geometric horizon.
C) The radar horizon is always less than the geometric horizon.
D) They are the same for the specific antenna height in the absence of refraction.
A
D) They are the same for the specific antenna height in the absence of refraction.
7
Q
What formula can be used to estimate the distance to the radar horizon ( d ) in nautical miles based on the height ( h ) of the antenna in feet, using a wavelength of 3 cm?
A) ( d = 1.22 \times h )
B) ( d = 1.22 \times \sqrt{h} )
C) ( d = 1.22 \times \frac{1}{h} )
D) ( d = 1.22 \times \frac{1}{\sqrt{h}} )
A
A) ( d = 1.22 \times h )
8
Q
What determines whether echoes can be received from targets beyond the radar horizon?
A) The height of the reflecting surface of the target
B) The frequency of the radar waves
C) The speed of the vessel
D) The curvature of the Earth
A
A) The height of the reflecting surface of the target
9
Q
What is the rate of decrease of pressure with height?
A) 3.6 mb/1000 ft
B) 10.13 mb/1000 ft
C) 36 mb/1000 ft
D) 1000 mb/36 ft
A
C) 36 mb/1000 ft
10
Q
What is the rate of decrease of temperature with height?
A) 0.2°C/1000 ft
B) 1.5°C/1000 ft
C) 2.0°C/1000 ft
D) 15.0°C/1000 ft
A
C) 2.0°C/1000 ft
11
Q
If the humidity is constant with height, what is the relative humidity at different altitudes?
A) It remains at 60% regardless of altitude.
B) It increases with altitude.
C) It decreases with altitude.
D) It fluctuates depending on atmospheric conditions.
A
A) It remains at 60% regardless of altitude.
12
Q
In which conditions does sub-refraction occur?
A) When warm air overrides cold air
B) When cold air overrides warm air
C) When there is no temperature difference between air layers
D) When there is a temperature inversion
A
A) When warm air overrides cold air
13
Q
What precautionary measures should be taken by the officer in charge of the watch in conditions of sub-refraction?
A) Increase speed and rely solely on radar for navigation.
B) Reduce speed and post extra lookouts.
C) Ignore the condition and maintain normal watch procedures.
D) Use only visual navigation methods and disregard radar information.
A
B) Reduce speed and post extra lookouts.
14
Q
What conditions lead to super-refraction?
A) When warm air overrides cold air
B) When cold air overrides warm air
C) When there is no temperature difference between air layers
D) When there is a temperature inversion
A
A) When warm air overrides cold air
15
Q
Under what conditions does super-refraction typically occur?
A) In calm weather with little or no turbulence
B) In stormy weather with high winds
C) In polar regions with extreme cold
D) In regions with frequent hurricanes
A
A) In calm weather with little or no turbulence or tropics
16
Q
What phenomenon occurs when energy radiated at angles of 1˚ or less is trapped in a layer of the atmosphere?
A) Super-refraction
B) Sub-refraction
C) Surface radio duct
D) Radar horizon
A
C) Surface radio duct
17
Q
What is the primary reason for the reduced chances of detecting targets above the surface radio duct?
A) Loss of energy in the radar rays escaping the duct
B) Interference from other vessels
C) Poor radar equipment quality
D) Atmospheric turbulence
A
A) Loss of energy in the radar rays escaping the duct
18
Q
What effect can ducting have on radar range?
A) Ducting increases the effective radar range.
B) Ducting has no effect on radar range.
C) Ducting reduces the effective radar range.
D) Ducting improves radar accuracy.
A
C) Ducting reduces the effective radar range.
19
Q
In which areas do ducting conditions occur?
A) Atlantic, Western Europe, Mediterranean, Arabian Sea, Bay of Bengal, and Pacific Ocean
B) Arctic, Antarctic, Indian Ocean, Red Sea, and Caribbean Sea
C) Pacific Ocean, Indian Ocean, Atlantic Ocean, Southern Ocean, and Arctic Ocean
D) Northern Hemisphere, Southern Hemisphere, Equatorial regions, Polar regions, and Subtropical regions
A
A) Atlantic, Western Europe, Mediterranean, Arabian Sea, Bay of Bengal, and Pacific Ocean
20
Q
What term describes the reduction in intensity of a wave as it propagates along its path?
A) Refraction
B) Reflection
C) Attenuation
D) Diffraction
A
C) Attenuation
21
Q
What are the typical effects of weather on radar operation?
A) Weather increases the ranges at which targets can be detected and reduces unwanted echoes.
B) Weather has no effect on radar operation.
C) Weather reduces the ranges at which targets can be detected and produces unwanted echoes.
D) Weather improves radar clarity and enhances target detection.
A
C) Weather reduces the ranges at which targets can be detected and produces unwanted echoes.
22
Q
What causes attenuation in radar waves?
A) Absorption and scattering of energy by precipitation
B) Reflection off solid surfaces
C) Refraction due to temperature changes
D) Diffraction around obstacles
A
A) Absorption and scattering of energy by precipitation
23
Q
At what wavelength does the effect of precipitation start to become of practical significance?
A) Longer than 10 cm
B) Shorter than 10 cm
C) Exactly 10 cm
D) It is not affected by wavelength
A
B) Shorter than 10 cm
24
Q
When does the effect of precipitation become significant in radar operation?
A) At wavelengths longer than 10 cm
B) At wavelengths shorter than 10 cm
C) At wavelengths longer than 100 cm
D) At wavelengths shorter than 100 cm
A
B) At wavelengths shorter than 10 cm
25
Which radar band typically suffers less attenuation in precipitation conditions?
A) S-band (10 cm)
B) X-band (3 cm)
C) L-band (15 cm)
D) C-band (5 cm)
A) S-band (10 cm)
26
How does encountering areas with industrial pollution, such as smog, affect radar signals compared to encountering sea fog?
A) Industrial pollution causes less attenuation than sea fog.
B) Industrial pollution causes more attenuation than sea fog.
C) Industrial pollution has no effect on radar signals.
D) Sea fog causes more attenuation than industrial pollution.
B) Industrial pollution causes more attenuation than sea fog.
27
Why are clouds typically not detected by radar at a 3 cm wavelength?
A) Cloud droplets are too large to produce a detectable response.
B) Cloud droplets are too small to produce a detectable response.
C) Clouds absorb radar waves at this wavelength.
D) Clouds reflect radar waves away from the radar system.
B) Cloud droplets are too small to produce a detectable response.
28
How does hail typically affect radar detection compared to rain?
A) Hail reflects radar energy more effectively than rain.
B) Hail reflects radar energy less effectively than rain.
C) Hail has no effect on radar detection.
D) Hail causes more attenuation than rain.
B) Hail reflects radar energy less effectively than rain.
29
When is falling snow typically observed on radar displays?
A) Falling snow is observed on both 3 cm and 10 cm radar displays.
B) Falling snow is observed only on 10 cm radar displays.
C) Falling snow is observed only on 3 cm radar displays.
D) Falling snow is not typically observed on radar displays.
C) Falling snow is observed only on 3 cm radar displays.
30
When might attenuation due to heavy snowfall be observed on radar displays?
A) Attenuation due to heavy snowfall is observed on both 3 cm and 10 cm radar displays.
B) Attenuation due to heavy snowfall is observed only on 10 cm radar displays.
C) Attenuation due to heavy snowfall is observed only on 3 cm radar displays.
D) Attenuation due to heavy snowfall is not typically observed on radar displays.
A) Attenuation due to heavy snowfall is observed on both 3 cm and 10 cm radar displays.
31
How does dust typically affect radar detection?
A) Dust particles produce detectable responses and cause significant attenuation.
B) Dust particles rarely produce detectable responses and cause minimal attenuation.
C) Dust particles produce detectable responses but cause minimal attenuation.
D) Dust particles rarely produce detectable responses but cause significant attenuation.
B) Dust particles rarely produce detectable responses and cause minimal attenuation.
32
In what range of pulses per second do the majority of modern marine radars operate?
A) 40 to 400
B) 400 to 4000
C) 4000 to 40,000
D) 40,000 to 400,000
B) 400 to 4000
33
How is the maximum measurable range typically determined in radar systems?
A) By dividing the radar's wavelength by the pulse repetition frequency (PRF)
B) By multiplying the radar's wavelength by the pulse repetition frequency (PRF)
C) By dividing the speed of light by the pulse repetition frequency (PRF)
D) By dividing 80,915 (radar nautical miles per second) by the pulse repetition frequency (PRF)
D) By dividing 80,915 (radar nautical miles per second) by the pulse repetition frequency (PRF)
34
How many pulses will a radar set produce for each degree of antenna rotation if the antenna is rotating at 15 revolutions per minute and the pulse repetition rate (PRR) is 800 pulses per second?
A) Approximately 6 pulses
B) Approximately 9 pulses
C) Approximately 12 pulses
D) Approximately 15 pulses
B) Approximately 9 pulses
35
How is pulse length typically defined in radar systems?
A) The distance traveled by the radar wave in one pulse
B) The duration of the transmitted radar pulse, usually measured in microseconds
C) The time it takes for the radar wave to return to the radar system
D) The frequency of the transmitted radar pulse
B) The duration of the transmitted radar pulse, usually measured in microseconds
36
What is the minimum range of a radar set with a pulse length of 1 microsecond?
A) 82 yards
B) 164 yards
C) 328 yards
D) 656 yards
B) 164 yards
37
What does it mean if a radar set has a minimum range of 164 yards with a pulse length of 1 microsecond?
A) Targets within this range will be displayed with reduced accuracy.
B) Targets within this range will not be detected due to masking by the transmitted pulse.
C) Targets within this range will be displayed with enhanced clarity.
D) Targets within this range will produce unusually strong echoes.
B) Targets within this range will not be detected due to masking by the transmitted pulse.
38
What is the approximate distance traveled by radio-frequency energy in 1 microsecond?
A) 0.082 nautical mile or 164 yards
B) 0.162 nautical mile or 328 yards
C) 0.328 nautical mile or 656 yards
D) 0.656 nautical mile or 1312 yards
B) 0.162 nautical mile or 328 yards
39
Why is the minimum detectable range for a target typically set at 164 yards when using a pulse length of 1 microsecond?
A) Because echoes from closer targets are too weak to be detected.
B) Because echoes from closer targets are masked by the transmitted pulse.
C) Because echoes from closer targets arrive after the radar pulse has already been transmitted.
D) Because echoes from closer targets interfere with echoes from farther targets.
B) Because echoes from closer targets are masked by the transmitted pulse.
40
What trade-off occurs when using a shorter pulse length in radar systems?
A) Maximum detection range capability is improved.
B) Maximum detection range capability is sacrificed for better range accuracy and resolution.
C) Maximum detection range capability remains unchanged.
D) Better range accuracy and resolution are sacrificed for maximum detection range capability.
B) Maximum detection range capability is sacrificed for better range accuracy and resolution.
41
What is the term for the useful power of the transmitter, contained in the radiated pulses?
A) Average power
B) Peak power
C) Pulse power
D) Transmit power
B) Peak power
42
What is the relationship between pulse repetition time (PRT) and pulse repetition rate (PRR)?
A) They are directly proportional.
B) They are inversely proportional.
C) They are equal.
D) They are unrelated.
B) They are inversely proportional.
43
What is the formula for average power in radar systems?
A) Average Power = pulse length / pulse repetition time
B) Average Power = pulse length * pulse repetition time
C) Average Power = pulse length + pulse repetition time
D) Average Power = pulse length - pulse repetition time
A) Average Power = pulse length / pulse repetition time
44
Sure, here's a multiple-choice question based on the provided information:
For a radar with a pulse length of 2 microseconds and a pulse repetition rate of 500 cycles per second (pulse repetition time = 2,000 microseconds), what is the average power of the radar?
A) 0.5 watts
B) 1 watt
C) 2 watts
D) 4 watts
C) 2 watts
45
Who issues Broadcast Notices to Mariners?
A) International Maritime Organization (IMO)
B) United Nations (UN)
C) International Hydrographic Organization (IHO)
D) United States Coast Guard (USCG)
D) United States Coast Guard (USCG)
46
Who issues Local Notices to Mariners?
A) International Maritime Organization (IMO)
B) United Nations (UN)
C) International Hydrographic Organization (IHO)
D) Local United States Coast Guard (USCG) district
D) Local United States Coast Guard (USCG) district
47
Who prepares Notices to Mariners in collaboration with the USCG and NOS and publishes them?
A) International Maritime Organization (IMO)
B) National Geospatial-Intelligence Agency (NGA)
C) United States Coast Guard (USCG)
D) National Oceanic and Atmospheric Administration (NOAA)
B) National Geospatial-Intelligence Agency (NGA)
48
What is a common practice in marking lateral buoys to maintain approximate sequence?
A) Omitting numbers
B) Adding numbers
C) Repeating numbers
D) Changing colors
A) Omitting numbers
49
In maritime navigation aids, what do letters signify when used alongside numbers?
A) A change in the navigational channel
B) An increase in the navigational hazard
C) The addition of lateral aids after a numerical sequence
D) A decrease in the water depth
Letters may be used to augment numbers where lateral aids are added after a previously
completed numerical sequence.
C) The addition of lateral aids after a numerical sequence
50
How are letters typically used in marking lateral buoys when aids are added after a numerical sequence?
A) Letters replace numbers
B) Letters are used to augment numbers
C) Letters are used instead of numbers
D) Letters are used to indicate priority
B) Letters are used to augment numbers
51
Which types of marks are always designated using letters rather than numbers?
A) Preferred channel, isolated danger, and special marks
B) Safe water, isolated danger, and special marks
C) Preferred channel, safe water, and information and regulatory aids
D) Preferred channel, safe water, isolated danger, and information and regulatory aids
D) Preferred channel, safe water, isolated danger, and information and regulatory aids
52
What does "discontinue" typically mean in the context of aids to navigation?
A) To relocate the aid
B) To repair the aid
C) To permanently or temporarily remove the aid from operation
D) To upgrade the aid
C) To permanently or temporarily remove the aid from operation
53
What does "withdraw" typically mean in the context of aids to navigation?
A) To relocate the aid
B) To repair the aid
C) To discontinue the aid during severe ice conditions or for the winter season
D) To upgrade the aid
C) To discontinue the aid during severe ice conditions or for the winter season
54
What does the term "Physical: fitted to an aid to navigation" imply?
A) The physical attributes of an aid to navigation
B) Equipment or components physically installed on an aid to navigation
C) The material composition of an aid to navigation
D) The geographical location of an aid to navigation
B) Equipment or components physically installed on an aid to navigation
55
What does the term "Synthetic: AtoN physical, AIS signal broadcast from shore" imply?
A) A physical aid to navigation with synthetic materials
B) A digital representation of an aid to navigation
C) A physical aid to navigation with an AIS signal broadcast from shore
D) A virtual representation of an aid to navigation
C) A physical aid to navigation with an AIS signal broadcast from shore
56
What does the term "Virtual: no physical AtoN, AIS signal broadcast from shore" imply?
A) A physical aid to navigation with virtual properties
B) A digital representation of an aid to navigation
C) A physical aid to navigation with an AIS signal broadcast from shore
D) A physical aid to navigation with no AIS signal broadcast
B) A digital representation of an aid to navigation
57
What are some characteristics of lateral buoys?
A) They are always fixed in place
B) They are typically painted red or green
C) They may exhibit various light characteristics such as flashing, quick flashing, group flashing, occulting, or isophase
D) They are used exclusively in deep water
C) They may exhibit various light characteristics such as flashing, quick flashing, group flashing, occulting, or isophase
58
What is true about white and yellow lights on aids to navigation?
A) They indicate the preferred channel
B) They mark the centerline of the fairway
C) They have no lateral significance
D) They indicate the presence of an obstruction
C) They have no lateral significance
59
What type of light characteristic is typically exhibited by preferred channel marks?
A) Quick flashing
B) Occulting
C) Composite group flashing
D) Isophase
C) Composite group flashing
60
What type of light characteristic is typically exhibited by safe water marks?
A) Flashing
B) Quick flashing
C) Morse A (*--)
D) Occulting
C) Morse A (*--)
61
What type of light characteristic is typically exhibited by isolated danger marks?
A) Quick flashing
B) Group flashing
C) Isophase
D) White (2) flashing rhythm
D) White (2) flashing rhythm
62
What type of light characteristic is typically exhibited by special marks?
A) Fixed or flashing red lights
B) Fixed or flashing green lights
C) Fixed or flashing yellow lights
D) Fixed or flashing white lights
C) Fixed or flashing yellow lights
63
What type of light characteristic is typically exhibited by information and regulatory marks?
A) Quick flashing
B) Flashing (2)
C) Morse A
D) White light with any rhythm except quick flashing, flashing (2), and Morse A
D) White light with any rhythm except quick flashing, flashing (2), and Morse A
64
What do the first letters "J," "K," "M," and "N" typically signify on dayboards?
A) They represent the geographic location
B) They indicate the distance from shore
C) They denote the type of aid to navigation
D) They classify the color of the dayboard
D) They classify the color of the dayboard
65
What does the first letter "J" typically indicate on a dayboard?
A) Junction
B) Range
C) Safe water
D) No lateral significance
A) Junction
66
What does the first letter "M" typically indicate on a dayboard?
A) Junction
B) Range
C) Safe water
D) No lateral significance
C) Safe water
67
What does the first letter "K" typically indicate on a dayboard?
A) Junction
B) Range
C) Safe water
D) No lateral significance
B) Range
68
What does the first letter "N" typically indicate on a dayboard?
A) Junction
B) Range
C) Safe water
D) No lateral significance
D) No lateral significance
69
What does the second letter typically indicate on a range dayboard?
A) Color of the outside stripes
B) Color of the inside stripe
C) Color of the top stripe
D) Color of the bottom stripe
A) Color of the outside stripes
70
What does the third letter typically indicate on a dayboard?
A) Color of the top stripe
B) Color of the bottom stripe
C) Color of the center stripe
D) Color of the outside stripes
C) Color of the center stripe
71
What does "NL" typically represent in marine navigation?
A) A safe water mark
B) A junction mark
C) A range mark
D) A location marker
D) A location marker
72
A rectangle white location marker with an orange reflective border and black letters indicating the location is typically used as a:
A) Safe water mark
B) Junction mark
C) Range mark
D) Location marker (NL)
D) Location marker (NL)
73
What does the code "NW" represent in terms of marine navigation aids?
A) Safe water mark
B) Junction mark
C) Range mark
D) Information or regulatory mark
D) Information or regulatory mark
74
What does "Class I" typically indicate in terms of marine navigation aids ownership?
A) The aid is privately owned and operated
B) The aid is owned by a governmental agency
C) The aid is maintained by a nonprofit organization
D) The aid is temporarily out of service
A) The aid is privately owned and operated
75
What does "Class II" typically indicate in terms of private aids to navigation?
A) They are located in waters used by general navigation
B) They are exclusively for commercial shipping
C) They are owned by governmental agencies
D) They are privately owned but not used for general navigation
A) They are located in waters used by general navigation
75
Lights and sound signals on oil wells or other offshore structures are not listed in the Light List unless:
A) They are equipped with a RACON
B) They are not considered navigational aids
C) They are temporary in nature
D) They are approved by the Coast Guard
A) They are equipped with a RACON
75
What does "Class III" typically indicate in terms of private aids to navigation?
A) They are located in waters used by general navigation
B) They are exclusively for commercial shipping
C) They are located in waters not ordinarily used by general navigation
D) They are privately owned but not used for general navigation
C) They are located in waters not ordinarily used by general navigation
76
In charts, heights are typically referenced above:
A) Mean low water
B) Mean high water
C) Mean sea level
D) Mean tide level
B) Mean high water
77
In maritime charts, heights of piers and wharves are usually referenced above:
A) Mean low water
B) Mean high water
C) Chart datum
D) Mean sea level
C) Chart datum
78
In maritime charts, drying heights are typically referenced above:
A) Mean low water
B) Mean high water
C) above Chart datum
D) Mean sea level
C) above Chart datum
79
In maritime charts, vertical clearances of bridges and cables are often indicated in:
A) Italics
B) Bold
C) Underlined
D) Regular font
B) Bold
80
Which color is used to represent safe vertical clearances of bridges and cables on the chart?
A) Red
B) Blue
C) Green
D) Magenta
D) Magenta
81
What color are fish havens tinted if the authorized depth is 11 fathoms or less?
A) Red
B) Yellow
C) Green
D) Blue
D) Blue
82
How do tidal currents on the west coast behave regarding diurnal inequality, which varies with the moon's declination?
A) They remain constant.
B) They vary with solar activity.
C) They fluctuate with wind patterns.
D) They vary with the moon's declination.
D) They vary with the moon's declination.
83
At which type of tide does diurnal inequality tend to disappear?
A) Neap tide
B) Spring tide
C) Equatorial tide
D) Lunar tide
C) Equatorial tide
84
In certain places, where might diurnal inequality be more pronounced in either the flood or ebb current?
A) Equatorial regions
B) Polar regions
C) Coastal regions
D) Mountainous regions
C) Coastal regions
85
In certain places, diurnal inequality may be more pronounced in either the flood or ebb current.
A) True
B) False
A) True
86
What is diurnal inequality?
A) It refers to the difference in tidal range between neap and spring tides.
B) It describes the variation in tidal currents throughout the day.
C) It represents the uneven distribution of tidal heights within a tidal cycle.
D) It signifies the difference in tidal heights or currents between consecutive high and low tides within a day.
D) It signifies the difference in tidal heights or currents between consecutive high and low tides within a day.
87
What causes a hydraulic current in a channel?
A) Difference in water salinity
B) Difference in water temperature
C) Difference in surface level at the two ends
D) Difference in water density
C) Difference in surface level at the two ends
88
What does "lunar interval" refer to?
A) The time it takes for the moon to complete one orbit around the Earth.
B) The difference in time between the moon's transit over the Greenwich meridian and a local meridian.
C) The period between consecutive new moons.
D) The duration of a lunar eclipse.
B) The difference in time between the moon's transit over the Greenwich meridian and a local meridian.
89
What does "lunicurrent interval" indicate?
A) The time it takes for the moon to complete one orbit around the Earth.
B) The time difference between the moon's transit over a meridian and a specific phase of the tidal current.
C) The duration between consecutive new moons.
D) The period during which the moon is visible in the night sky.
B) The time difference between the moon's transit over a meridian and a specific phase of the tidal current.
90
What characterizes a mixed tide?
A) Large inequality in high and/or low water heights.
B) Consistent high and low water heights.
C) Regular intervals between high and low tides.
D) Uniform tidal currents throughout the day.
A) Large inequality in high and/or low water heights.
91
What defines a vanishing tide?
A) Lower high or higher low water that becomes indistinct at times of extreme declinations.
B) Consistently high water levels.
C) Rapid fluctuations in water levels.
D) Sudden changes in tidal currents.
A) Lower high or higher low water that becomes indistinct at times of extreme declinations.
92
Which statement accurately describes the characteristics of perigean and apogean tidal current speeds?
A) Perigean tidal current speeds are consistently below average, while apogean speeds are consistently above average.
B) Perigean tidal current speeds are 15 to 20% above average, while apogean speeds are 30 to 40% below average.
C) Perigean tidal current speeds are 15 to 20% below average, while apogean speeds are 30 to 40% above average.
D) Perigean tidal current speeds are 30 to 40% above average, while apogean speeds are 15 to 20% below average.
B) Perigean tidal current speeds are 15 to 20% above average, while apogean speeds are 30 to 40% below average.
93
What does "Indian spring low water" refer to?
A) A low water datum that includes the spring effect of the full or new moon and the tropic effect of the moon at maximum declination.
B) The lowest water level observed in Indian coastal areas during spring tides.
C) The lowest water level observed in Indian coastal areas during neap tides.
D) A tidal epoch specific to Indian oceanic regions.
A) A low water datum that includes the spring effect of the full or new moon and the tropic effect of the moon at maximum declination.
94
What does "geodesy" involve?
A) The study of geological formations and their evolution over time.
B) The analysis of seismic activity and its impact on tectonic plates.
C) The application of mathematics to model the size and shape of the physical Earth.
D) The exploration of caves and underground structures.
Correct Answer: C) The application of mathematics to model the size and shape of the physical Earth.
95
What does the term "geoid" refer to?
A) A flat surface used as a reference for mapping elevations.
B) The surface of the Earth that is closest to the center of mass.
C) A surface along which gravity is always equal and to which the direction of gravity is always perpendicular.
D) A mathematical model of the Earth's shape assuming uniform density.
C) A surface along which gravity is always equal and to which the direction of gravity is always perpendicular.
96
What is an ellipsoid in the context of geodesy?
A) A spherical representation of the Earth's surface.
B) A flat projection used for mapping large areas.
C) An irregular shape representing the Earth's surface.
D) An approximation of the geoid with a specific mathematical expression.
D) An approximation of the geoid with a specific mathematical expression.
97
What do geoidal heights, geoidal undulations, or geoidal separations represent?
A) The distance between two geographical points on the Earth's surface.
B) The difference in elevation between the highest and lowest points on the Earth's surface.
C) The separation of the geoid and the ellipsoid.
D) The variations in gravitational pull across different regions of the Earth.
C) The separation of the geoid and the ellipsoid.
98
What does "ellipsoid height" indicate?
A) The distance between two geographical points on the Earth's surface.
B) The height of a point above or below sea level.
C) The distance between the Earth's surface and the center of mass.
D) The distance a given point is above or below the ellipsoid surface.
D) The distance a given point is above or below the ellipsoid surface.
99
What does "geoid height" represent?
A) The distance between two geographical points on the Earth's surface.
B) The height of a point above or below sea level.
C) The distance between the Earth's surface and the center of mass.
D) The distance the geoid surface is above or below the ellipsoid surface.
D) The distance the geoid surface is above or below the ellipsoid surfac
100
What does "horizontal geodetic datum" consist of?
A) The astronomic and geodetic latitude and astronomic and geodetic longitude of an initial point; an azimuth of a line; the parameters of the ellipsoid selected for the computations; and the geoidal separation at the origin.
B) The angle between the plane of the celestial meridian at Greenwich and the plane of the local meridian.
C) The angle between the plane of the celestial equator and a plumb line.
D) The angle at the center of the ellipsoid between the plane of the equator and a straight line to a point on the surface of the ellipsoid.
A) The astronomic and geodetic latitude and astronomic and geodetic longitude of an initial point; an azimuth of a line; the parameters of the ellipsoid selected for the computations; and the geoidal separation at the origin.
101
What is "geodetic latitude"?
A) The angle between the plane of the celestial meridian at Greenwich and the plane of the local meridian.
B) The angle between the plane of the celestial equator and a plumb line.
C) The angle which the normal to the ellipsoid at a station makes with the plane of the geodetic equator.
D) The angle between the plane of the equator and a straight line to a point on the surface of the ellipsoid.
C) The angle which the normal to the ellipsoid at a station makes with the plane of the geodetic equator.
102
What does "astronomic latitude" represent?
A) The angle between the plane of the celestial meridian at Greenwich and the plane of the local meridian.
B) The angle between the plane of the celestial equator and a plumb line.
C) The angle which the normal to the ellipsoid at a station makes with the plane of the geodetic equator.
D) The angle between the plane of the equator and a straight line to a point on the surface of the ellipsoid.
B) The angle between the plane of the celestial equator and a plumb line.
103
Which statement accurately describes "orthometric height"?
A) It is the angle between a plumb line and the plane of the celestial equator.
B) It is the height from the geoid to the vertical reference surface used to approximate mean sea level.
C) It is the angle which the normal to the ellipsoid at a station makes with the plane of the geodetic equator.
D) It is the angle at the center of the ellipsoid between the plane of the equator and a straight line to a point on the surface of the ellipsoid.
B) It is the height from the geoid to the vertical reference surface used to approximate mean sea level.
104
What does "astronomic longitude" represent?
A) The angle between the plane of the celestial meridian at Greenwich and the plane of the local meridian.
B) The angle between the plane of the celestial equator and a plumb line.
C) The angle which the normal to the ellipsoid at a station makes with the plane of the geodetic equator.
D) The angle between the plane of the equator and a straight line to a point on the surface of the ellipsoid.
A) The angle between the plane of the celestial meridian at Greenwich and the plane of the local meridian.
105
What does "geodetic longitude" represent?
A) The angle between the plane of the celestial meridian at Greenwich and the plane of the local meridian.
B) The angle between the plane of the celestial equator and a plumb line.
C) The angle which the normal to the ellipsoid at a station makes with the plane of the geodetic equator.
D) The angle between the plane of the geodetic meridian at Greenwich and the plane of the local meridian.
D) The angle between the plane of the geodetic meridian at Greenwich and the plane of the local meridian.
106
Which type of triangulation is the most precise and exact, typically used for control points?
A) First-order triangulation
B) Second-order triangulation
C) Third-order triangulation
D) Fourth-order triangulation
Correct Answer: A) First-order triangulation
107
What is the purpose of third-order triangulation?
A) To ensure no appreciable errors occur on maps.
B) To measure the sides of a chain of triangles.
C) To densify a survey by running between points in a secondary survey.
D) To establish control points for precise measurements.
Correct Answer: C) To densify a survey by running between points in a secondary survey.
108
What does trilateration involve?
A) Measuring the sides of a chain of triangles.
B) Ensuring no appreciable errors occur on maps.
C) Surveying points closer together that are tied to a primary system.
D) Establishing control points for precise measurements.
Correct Answer: A) Measuring the sides of a chain of triangles.
109
Which triangulation survey involves points that are closer together and are tied to a primary system?
A) First-order triangulation
B) Second-order triangulation
C) Third-order triangulation
D) Fourth-order triangulation
B) Second-order triangulation
110
What is traversing primarily concerned with?
A) Measuring distances and angles between points without triangles.
B) Determining elevations above mean sea level.
C) Establishing a basic network of vertical control points.
D) Measuring the sides of triangles to determine positions.
Correct Answer: A) Measuring distances and angles between points without triangles.
111
What does vertical surveying involve?
A) Measuring distances and angles between points without triangles.
B) Determining elevations above mean sea level.
C) Establishing a basic network of vertical control points.
D) Measuring the sides of triangles to determine positions.
Correct Answer: B) Determining elevations above mean sea level.
112
What is the primary purpose of leveling?
A) Measuring distances and angles between points without triangles.
B) Determining elevations above mean sea level.
C) Establishing a basic network of vertical control points.
D) Measuring the sides of triangles to determine positions.
Correct Answer: C) Establishing a basic network of vertical control points.
113
What does differential leveling involve?
A) Readings made on two calibrated staffs.
B) Vertical angle measured from a known distance with a theodolite.
C) Determining differences in height by measuring difference in atmospheric pressure.
D) Measuring distances and angles between points without triangles.
Correct Answer: A) Readings made on two calibrated staffs.
114
What is trigonometric leveling primarily concerned with?
A) Readings made on two calibrated staffs.
B) Vertical angle measured from a known distance with a theodolite.
C) Determining differences in height by measuring difference in atmospheric pressure.
D) Measuring distances and angles between points without triangles.
Correct Answer: B) Vertical angle measured from a known distance with a theodolite.
115
What does barometric leveling involve?
A) Readings made on two calibrated staffs.
B) Vertical angle measured from a known distance with a theodolite.
C) Determining differences in height by measuring difference in atmospheric pressure.
D) Measuring distances and angles between points without triangles.
Correct Answer: C) Determining differences in height by measuring difference in atmospheric pressure.
116
What is the speed of radar waves?
A) 300,000 km/s or 328 yds/µs
B) 162,000 nm/s or 328 yds/µs
C) 300 KM/s or 122 yds/us
D) 300 m/µs
A) 300,000 km/s or 328 yds/µs
117
What is the typical range for pulse length in radar systems?
A) Between 0.05 and 0.1 µs
B) Between 0.5 and 1.0 µs
C) Between 0.01 and 0.05 µs
D) Between 1.0 and 1.5 µs
B) Between 0.5 and 1.0 µs
118
What is the typical range for Pulses per Second (PRR) in radar systems?
A) Between 50 and 400
B) Between 500 and 1,000
C) Between 500 and 4,000
D) Between 4,000 and 8,000
C) Between 500 and 4,000
119
What is the typical range for horizontal beam widths in radar systems?
A) Between 0.05 and 0.2°
B) Between 0.2 and 0.5°
C) Between 0.5 and 2.0°
D) Between 2.0 and 4.0°
C) Between 0.5 and 2.0°
120
What is the typical range for vertical beam widths in radar systems?
A) Between 5 and 15°
B) Between 15 and 30°
C) Between 30 and 45°
D) Between 45 and 60°
B) Between 15 and 30°
121
What factor is bearing resolution in radar systems proportional to and inversely proportional to?
A) Proportional to antenna length and reciprocal to wavelength.
B) Proportional to wavelength and reciprocal to antenna length.
C) Proportional to pulse length and reciprocal to pulse repetition frequency.
D) Proportional to wavelength and reciprocal to pulse length.
A) Proportional to antenna length and reciprocal to wavelength.
122
What is the recommended criterion for choosing antenna length based on bearing width in radar systems?
A) Antenna length should be chosen for a bearing width of 5° or less.
B) Antenna length should be chosen for a bearing width of 2.5° or less.
C) Antenna length should be chosen for a bearing width of 10° or less.
D) Antenna length should be chosen for a bearing width of 1° or less.
B) Antenna length should be chosen for a bearing width of 2.5° or less.
123
What is the recommended length for an S-band radiator in radar systems?
A) 6 ft or longer
B) 8 ft or longer
C) 10 ft or longer
D) 12 ft or longer
Correct Answer: D) 12 ft or longer
Correct Answer: D) 12 ft or longer
124
What is the recommended length for an X-band radiator in radar systems?
A) 2 ft or longer
B) 4 ft or longer
C) 6 ft or longer
D) 8 ft or longer
Correct Answer: B) 4 ft or longer
125
What factors contribute to better range resolution in radar systems?
A) Shorter pulse length, less receiver gain, shorter range scale.
B) Longer pulse length, higher receiver gain, longer range scale.
C) Longer pulse length, less receiver gain, shorter range scale.
D) Shorter pulse length, higher receiver gain, longer range scale.
A) Shorter pulse length, less receiver gain, shorter range scale.
126
What condition ensures that two targets on the same bearing will be distinct in radar systems?
A) The distance between the targets should be less than half the pulse width.
B) The distance between the targets should be greater than half the pulse width.
C) The distance between the targets should be less than the pulse repetition frequency.
D) The distance between the targets should be greater than the wavelength.
B) The distance between the targets should be greater than half the pulse width.
127
What factor primarily influences bearing accuracy in radar systems?
A) Horizontal beam width
B) Vertical beam width
C) Pulse repetition frequency
D) Antenna length
A) Horizontal beam width
128
How does the beam width correction vary for different aspects of a vessel relative to the radar?
A) Negative for port bow and starboard quarter, positive for starboard bow and port quarter.
B) Positive for port bow and starboard quarter, negative for starboard bow and port quarter.
C) Negative for both port and starboard sides.
D) Positive for both port and starboard sides.
B) Positive for port bow and starboard quarter, negative for starboard bow and port quarter.
129
How does positive and negative range errors affect beam width error in radar systems?
A) Positive range error reduces beam width error, negative range error adds to beam width error.
B) Positive range error adds to beam width error, negative range error reduces beam width error.
C) Both positive and negative range errors add to beam width error.
D) Both positive and negative range errors reduce beam width error.
B) Positive range error adds to beam width error, negative range error reduces beam width error.
130
How should the misalignment of the starboard heading marker be adjusted for radar bearings and PI lines?
A) Subtract for radar bearings, subtract for PI lines.
B) Add for radar bearings, add for PI lines.
C) Subtract for radar bearings, add for PI lines.
D) Add for radar bearings, subtract for PI lines..
C) Subtract for radar bearings, add for PI lines.
131
How should the misalignment of the port heading marker be adjusted for radar bearings and PI lines?
A) Add for radar bearings, add for PI lines.
B) Subtract for radar bearings, subtract for PI lines.
C) Add for radar bearings, subtract for PI lines.
D) Subtract for radar bearings, add for PI lines.
C) Add for radar bearings, subtract for PI lines.
132
How does range error distortion affect PI orientation and cross index range in radar systems?
A) It affects PI orientation but not cross index range.
B) It affects cross index range but not PI orientation.
C) It affects both PI orientation and cross index range.
D) It does not affect either PI orientation or cross index range.
C) It affects both PI orientation and cross index range.
133
What factors affect PI (Parallel Indexing) orientation in radar systems?
A) Gyro error and range error distortion.
B) Heading marker misalignment and beam width error.
C) Gyro error, heading marker misalignment, beam width error, and range error distortion.
D) Only range error distortion.
C) Gyro error, heading marker misalignment, beam width error, and range error distortion.
134
What factors are not considered in dead reckoning position?
A) Wind and current
B) Course and speed through the water
C) Only wind
D) Only current
A) Wind and current
135
What is considered in estimated reckoning?
A) Set and drift
B) Course and speed through the water
C) Only set
D) Only drift
A) Set and drift
