OCE 1001 Ch. 9 Questions with Correct Answers (Grade A+)
Question 1: Why is the idealized highest high tide at 28 degrees south latitude delayed by 12 hours from
the highest high tide at 28 degrees north latitude?
Answer: That is how long it takes for the location at 28 degrees south latitude to rotate into the largest part
of the high tide bulge
Question 2: It is Wednesday, and you are planning a fishing trip for this coming Saturday. You have
heard that fishing is best at your chosen spot when the ebb current begins to flow, so you wish to start
fishing at high tide. You do not have a tide table, but you have noted that today's high tide was at 1:10
p.m. At what time on Saturday should you plan to arrive and start fishing?
Answer: 3:40 PM
Question 3: A proxigean tide occurs when __________.
Answer: the Moon is at perigee at a time of syzygy
Question 4: Which of the following statements about tides in a simple tidal bulge model is/are true?
Choose all that apply.
Answer: -Tides are greatest when the Moon is at perigee and Earth is at perihelion. -A lunar or solar eclipse
can occur only when the Moon is in syzygy. -Neap tides result from destructive interference between the
solar and lunar tidal bulges. -Spring tides result from constructive interference between the solar and lunar
tidal bulges.
Question 5: A relatively small tidal range could be expected __________.
Answer: at an amphidromic point
Question 6: The tides are considered an example of shallow-water waves because the tidal bulges have a
wavelength that is on the order of __________.
Answer: thousands of kilometers
Question 7: Which of the following statements about tidal patterns and tidal charts is/are true? Choose
all that apply.
Answer: -A semidiurnal tidal pattern has two low tides every tidal day. -A tidal day is 24 hours and 50
minutes long. -A mixed tidal pattern has two lows of unequal height and two highs of unequal height every
tidal day. -The tidal range is the difference in height between a high tide and a low tide.
Page 1
, Question 8: Which phase(s) of the moon result in a low tidal range? Choose all that apply.
Answer: -third quarter moon -first quarter moon
Question 9: Some of the tide height numbers in your tide table are preceded by minus signs (or in some
cases printed in red). This tells you that __________.
Answer: spring tides are occurring
Question 10: A boat is most likely to be carried out to sea from a harbor by a(n) __________.
Answer: ebb current
Question 11: A grunion "run" would be expected within a few nights after __________.
Answer: a new or full moon
Question 12: Disadvantages of tidal power plants relative to conventional thermal plants include higher
initial plant costs, periodicity of tidal currents, and __________.
Answer: impacts on the marine environment
Question 13: If it is January and the Moon is in syzygy, which additional factor would contribute to
extreme tidal ranges around the world?
Answer: The moon is in perigee
Question 14: Of the following statements about the monthly tidal cycle, which is/are true? Choose all
that apply.
Answer: -Spring tides occur twice a month. -Neap tides occur twice a month. -The full moon and the new
moon affect the tides about the same. -The full moon is associated with spring tide conditions.
Question 15: Of the following statements about lunar phases, which is/are true? Choose all that apply.
Answer: -Over the few days of a waxing crescent moon, the tidal range decreases. -Over the few days of a
waxing gibbous moon, the tidal range increases.
Question 16: In an amphidromic cell with a normal tidal cycle, what cotidal line would experience high
tide if low tide were occurring along cotidal line 2?
Answer: 8
Page 2
Question 1: Why is the idealized highest high tide at 28 degrees south latitude delayed by 12 hours from
the highest high tide at 28 degrees north latitude?
Answer: That is how long it takes for the location at 28 degrees south latitude to rotate into the largest part
of the high tide bulge
Question 2: It is Wednesday, and you are planning a fishing trip for this coming Saturday. You have
heard that fishing is best at your chosen spot when the ebb current begins to flow, so you wish to start
fishing at high tide. You do not have a tide table, but you have noted that today's high tide was at 1:10
p.m. At what time on Saturday should you plan to arrive and start fishing?
Answer: 3:40 PM
Question 3: A proxigean tide occurs when __________.
Answer: the Moon is at perigee at a time of syzygy
Question 4: Which of the following statements about tides in a simple tidal bulge model is/are true?
Choose all that apply.
Answer: -Tides are greatest when the Moon is at perigee and Earth is at perihelion. -A lunar or solar eclipse
can occur only when the Moon is in syzygy. -Neap tides result from destructive interference between the
solar and lunar tidal bulges. -Spring tides result from constructive interference between the solar and lunar
tidal bulges.
Question 5: A relatively small tidal range could be expected __________.
Answer: at an amphidromic point
Question 6: The tides are considered an example of shallow-water waves because the tidal bulges have a
wavelength that is on the order of __________.
Answer: thousands of kilometers
Question 7: Which of the following statements about tidal patterns and tidal charts is/are true? Choose
all that apply.
Answer: -A semidiurnal tidal pattern has two low tides every tidal day. -A tidal day is 24 hours and 50
minutes long. -A mixed tidal pattern has two lows of unequal height and two highs of unequal height every
tidal day. -The tidal range is the difference in height between a high tide and a low tide.
Page 1
, Question 8: Which phase(s) of the moon result in a low tidal range? Choose all that apply.
Answer: -third quarter moon -first quarter moon
Question 9: Some of the tide height numbers in your tide table are preceded by minus signs (or in some
cases printed in red). This tells you that __________.
Answer: spring tides are occurring
Question 10: A boat is most likely to be carried out to sea from a harbor by a(n) __________.
Answer: ebb current
Question 11: A grunion "run" would be expected within a few nights after __________.
Answer: a new or full moon
Question 12: Disadvantages of tidal power plants relative to conventional thermal plants include higher
initial plant costs, periodicity of tidal currents, and __________.
Answer: impacts on the marine environment
Question 13: If it is January and the Moon is in syzygy, which additional factor would contribute to
extreme tidal ranges around the world?
Answer: The moon is in perigee
Question 14: Of the following statements about the monthly tidal cycle, which is/are true? Choose all
that apply.
Answer: -Spring tides occur twice a month. -Neap tides occur twice a month. -The full moon and the new
moon affect the tides about the same. -The full moon is associated with spring tide conditions.
Question 15: Of the following statements about lunar phases, which is/are true? Choose all that apply.
Answer: -Over the few days of a waxing crescent moon, the tidal range decreases. -Over the few days of a
waxing gibbous moon, the tidal range increases.
Question 16: In an amphidromic cell with a normal tidal cycle, what cotidal line would experience high
tide if low tide were occurring along cotidal line 2?
Answer: 8
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