Nitrox
Quiz settings
Property
Setting
Passing score
80%
Display Point Value
Yes
Randomize Questions
Yes
Total Number of Questions
30
Total Number of Questions to Ask
All
Display User Score
Yes
Display Passing Score
Yes
Display Pass/Fail Messages
Yes
Email recipient
Questions
Multiple Choice, 10 points, 1 attempt(s) permitted.
1. A diver wishes to plan two nitrox dives using EAN36 and NN36 tables. The first dive will be to
a depth of 100ft for 20 minutes. Following a one hour surface interval, how long may the diver
stay at 60ft on the second dive?
Correct
Choice
29 minutes
X
71 minutes
100 minutes
62 minutes
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
2. A dive team plans a dive to a maximum depth of 70ft using EAN32 with NN32 tables and a PO2
of 1.6. What is the maximum depth the divers should descend on the dive?
Correct
Choice
Feedback
132'
Incorrect. The dive plan called for a miximum
depth of 70 feet. Plan your dive and dive your
plan.
65'
Incorrect. The divers can decend to their
maximum planned depth of 70 feet.
X
130'
Incorrect. The dive plan called for a miximum
depth of 70 feet. Plan your dive and dive your
plan.
70'
Correct. Even though the MOD of the gas is
deeper, the divers should not exceed the
maximum planned depth for the dive.
Multiple Choice, 10 points, 1 attempt(s) permitted.
3. What is the absolute pressure (ata) at 75 fsw?
Correct
Choice
X
3.27 ata
2.37 ata
3.72 ata
7.32 ata
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
4. A dive team wants to make a dive using NN32 and a PO2 of 1.6, what is the MOD for the mix?
Correct
X
Choice
Feedback
130'
Incorrect. The MOD for a 32% mix at a PO2 of
1.6 is 132'.
132'
Correct
110'
Incorrect. The MOD for a 32% mix at a PO2 of
1.6 is 132'.
190'
Incorrect. The MOD for a 32% mix at a PO2 of
1.6 is 132'.
Multiple Choice, 10 points, 1 attempt(s) permitted.
5. The maximum oxygen partial pressure exposure for scientific diving is ___, and you may want
to further limit your exposure.
Correct
X
Choice
Feedback
1.3
Incorrect. The maximum PO2 for scientific
diving is 1.6.
1.4
Incorrect. The maximum PO2 for scientific
diving is 1.6.
1.5
Incorrect. The maximum PO2 for scientific
diving is 1.6.
1.6
Correct
1.8
Incorrect. The maximum PO2 for scientific
diving is 1.6.
Multiple Choice, 10 points, 1 attempt(s) permitted.
6. The maximum oxygen partial pressure exposure for recreational diving is ___.
Correct
X
Choice
Feedback
1.3
Incorrect. The maximum PO2 for recreational
diving is 1.4.
1.4
Correct
1.5
Incorrect. The maximum PO2 for recreational
diving is 1.4.
1.6
Incorrect. The maximum PO2 for recreational
diving is 1.4.
1.8
Incorrect. The maximum PO2 for recreational
diving is 1.4.
Multiple Choice, 10 points, 1 attempt(s) permitted.
7. According to the NOAA Oxygen Exposure Limits Table 15.2 (page 15-5 of the NOAA Diving
Manual), the maximum single dive exposure time for a PO2 exposure of 1.2 is ___ minutes.
Correct
X
Choice
Feedback
45
Incorrect. The maximum single dive exposure
time for a PO2 of 1.2 is 210 minutes.
150
Incorrect. The maximum single dive exposure
time for a PO2 of 1.2 is 210 minutes.
210
Correct
240
Incorrect. The maximum single dive exposure
time for a PO2 of 1.2 is 210 minutes.
Multiple Choice, 10 points, 1 attempt(s) permitted.
8. Calculate the maximum operating depth (MOD) for a 33% nitrox mix using a PO2 exposure at
depth of 1.6.
Correct
Choice
X
127 fsw
31.4 fsw
60 fsw
99 fsw
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
9. Calculate the MOD of a 50% nitrox mix using a PO2 exposure at depth of 1.5.
Correct
Choice
50 fsw
X
66 fsw
75 fsw
82 fsw
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
10. Calculate the maximum operating depth (MOD) for a 21% nitrox mix using a PO2 exposure at
depth of 1.6.
Correct
Choice
130 fsw
203 fsw
187 fsw
X
218 fsw
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
11. Calculate the partial pressure of O2 (PO2) for air being breathed at 90 fsw.
Correct
X
Choice
Feedback
.78
Correct
.21
Incorrect. Multiply the absolute pressure by
the percentage of the gas in question to find
the correct answer of .78.
.57
Incorrect. Multiply the absolute pressure by
the percentage of the gas in question to find
the correct answer of .78.
1.6
Incorrect. Multiply the absolute pressure by
the percentage of the gas in question to find
the correct answer of .78.
Multiple Choice, 10 points, 1 attempt(s) permitted.
12. Calculate the partial pressure of Nitrogen (PN2) for air being breathed at 90 fsw.
Correct
X
Choice
Feedback
2.9
Correct
1.6
Incorrect. Multiply the absolute pressure at 90
fsw by the percentage of nitrogen in air to find
the correct answer of 2.9.
.78
Incorrect. Multiply the absolute pressure at 90
fsw by the percentage of nitrogen in air to find
the correct answer of 2.9.
2.1
Incorrect. Multiply the absolute pressure at 90
fsw by the percentage of nitrogen in air to find
the correct answer of 2.9.
Multiple Choice, 10 points, 1 attempt(s) permitted.
13. Calculate the partial pressure of O2 (PO2) for a 36% nitrox mix being breathed at 130 fsw. As
a scientific diver, would you want to make this dive?
Correct
X
Choice
Feedback
1.6 / Yes
Incorrect. You did not calculate the PO2
correctly, and the dive exceeds the PO2 limit of
1.6.
1.78 / Yes
Incorrect. You calculated the PO2 correctly, but
you would not want to make this dive because
you exceeded the 1.6 PO2 limit.
1.6 / No
Incorrect. You did not calculate the PO2
correctly, but you were correct by not wanting
to make the dive; it exceeds the 1.6 PO2 limit.
1.78 / No
Correct
Multiple Choice, 10 points, 1 attempt(s) permitted.
14. You need to maximize your no-stop dive time for a dive to 60 fsw. Calculate the best nitrox mix
for this dive using a maximum PO2 exposure at depth of 1.6.
Correct
X
Choice
Feedback
40%
Incorrect. To calculate Best Mix divide the PO2
by the absolute pressure. 1.6/2.82=.57
57%
Correct
32%
Incorrect. To calculate Best Mix divide the PO2
by the absolute pressure. 1.6/2.82=.57
36%
Incorrect. To calculate Best Mix divide the PO2
by the absolute pressure. 1.6/2.82=.57
Multiple Choice, 10 points, 1 attempt(s) permitted.
15. You need to maximize your no-stop dive time for a dive to 140 fsw. Calculate the best nitrox
mix for this dive using a maximum PO2 exposure at depth of 1.5.
Correct
X
Choice
Feedback
21%
Incorrect. To calculate Best Mix divide the PO2
by the absolute pressure. 1.5/5.24=.29
29%
Correct
32%
Incorrect. To calculate Best Mix divide the PO2
by the absolute pressure. 1.5/5.24=.29
35%
Incorrect. To calculate Best Mix divide the PO2
by the absolute pressure. 1.5/5.24=.29
Multiple Choice, 10 points, 1 attempt(s) permitted.
16. The _______ is the depth based on the partial pressure of nitrogen in the gas mixture to be
breathed, rather than the actual depth of the dive. This was the concept used to develop NOAA
nitrox dive tables.
Correct
X
Choice
Feedback
residual nitrogen time (RNT)
Incorrect. Equivalent air depth (EAD) is the
correct answer.
equivalent nitrox depth (END)
Incorrect. Equivalent air depth (EAD) is the
correct answer.
maximum operating depth (MOD)
Incorrect. Equivalent air depth (EAD) is the
correct answer.
equivalent air depth (EAD)
Correct
Multiple Choice, 10 points, 1 attempt(s) permitted.
17. You are using an air based dive computer to compute your decompression profile. You are
breathing a 36% nitrox mix and your maximum PO2 exposure limit at depth is 1.6. The bottom is
130 fsw. Your dive plan calls for a dive to 110 fsw for 30 minutes. Which of the following is a
major concern?
Correct
Choice
Your risk of decompression sickness is lower because you are using a nitrox based dive computer
and breathing air.
X
Your air based dive computer thinks you are breathing air, air based computers do not have any
MOD alarms in place, and the maximum possible depth of the dive exceeds the MOD for the mix
you will be breathing.
Your planned dive time will exceed the single dive oxygen exposure limit for a PO2 of 1.6.
Your risk of decompression sickness is higher because you are using an air based dive computer
and breathing nitrox.
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
18. Use NOAA NN32 dive tables to calculate a dive to 75 fsw for 35 minutes followed by a 1:30 SIT
and a second dive to 75 fsw for 20 minutes. What is the ESDT of the second dive and the ending
letter group?
Correct
Choice
20 minutes, E
24 minutes, F
50 minutes, H
X
46 minutes, J
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
19. What is the EAD (Equivalent Air Depth) of a dive with an actual depth of 100 fsw where the
diver is breathing 36% nitrox?
Correct
X
Choice
Feedback
65 fsw
Incorrect. EAD fsw= (((depth fsw+33)(1FO2))/.79)-33. Or you can use Table 15.6 in the
NOAA Diving Manual.
70 fsw
Incorrect. EAD fsw= (((depth fsw+33)(1FO2))/.79)-33. Or you can use Table 15.6 in the
NOAA Diving Manual.
75 fsw
Correct
80 fsw
Incorrect. EAD fsw= (((depth fsw+33)(1FO2))/.79)-33. Or you can use Table 15.6 in the
NOAA Diving Manual.
Multiple Choice, 10 points, 1 attempt(s) permitted.
20. The _______ method of blending nitrox requires ultra clean air, O2 clean valves and cylinders.
100% O2 is trans-filled into a scuba cylinder then topped with air.
Correct
Choice
Membrane Separation
Pressure Swing Adsorption
Continue Flow Mixing
X
Partial-Pressure Mixing
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
21. In the ______ method of blending nitrox, oxygen is metered into the air being drawn into a
compressor. This requires an "oil free" compressor and the 40% rule applies.
Correct
Choice
Membrane Separation
Pressure Swing Adsorption
X
Continuous Flow Mixing
Partial-Pressure Mixing
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
22. The _______ method of blending nitrox works by forcing clean low-pressure air through a
membrane that allows oxygen to pass more readily than nitrogen.
Correct
X
Choice
Membrane Separation
Pressure Swing Adsorption
Continuous Flow Mixing
Partial-Pressure Mixing
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
23. Ideally, oxygen analyzers should have a resolution accuracy of ________.
Correct
Choice
0.01% (one-hunderth of one percent)
X
0.1% (one-tenth of one percent)
1% (one percent)
10% (ten percent)
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
24. The heart of an oxygen analyzer is its detection method. There are two primary types
Paramagnetic and Electrochemical. _________ analyzers are relatively inexpensive, can be
portable, are rugged, and show little interference from other gases. They may need frequent
calibration, especially as the O2 sensor cell begins to age.
Correct
Choice
Paramagnetic
X
Electrochemical
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Response, 10 points, 1 attempt(s) permitted.
25. Once analyzed, the contents of cylinder must be recorded on a cylinder contents label, and this
label is to be placed on the analyzed cylinder. This label contains _________. (select all that apply)
Correct
Choice
X
the percentage of O2 in the mix
X
the date
X
the MOD
X
the initials of the diver analyzing the mix
Feedback when correct: Correct
Feedback when incorrect: Incorrect
True/False, 10 points, 1 attempt(s) permitted.
26. Nitrox is safer than air.
Correct
Choice
True
X
False
Feedback when correct: Correct
Feedback when incorrect: Incorrect
True/False, 10 points, 1 attempt(s) permitted.
27. Nitrox has very stringent depth limits because of the higher concentration of O2 in the
mixture. (Nitrox has very stringent depth limits because of the higher concentration of O2 in the
mixture.)
Correct
X
Choice
True
False
Feedback when correct: Correct
Feedback when incorrect: Incorrect
True/False, 10 points, 1 attempt(s) permitted.
28. Nitrox provides the greatest advantages for no-stop diving in the 50-110 fsw depth range.
Correct
X
Choice
True
False
Feedback when correct: Correct
Feedback when incorrect: Incorrect
Multiple Choice, 10 points, 1 attempt(s) permitted.
29. Nitrox reduces narcosis.
Correct
X
Choice
Feedback
Yes
Incorrect. Oxygen’s properties suggest that it
can also be a narcotic gas under pressure. The
result is that you should not expect a
significant change in narcosis when diving
nitrox as compared to air.
No
Incorrect. Oxygen’s properties suggest that it
can also be a narcotic gas under pressure. The
result is that you should not expect a
significant change in narcosis when diving
nitrox as compared to air.
Not Really
Correct
True/False, 10 points, 1 attempt(s) permitted.
30. Nitrox makes treatment for DCS impossible.
Correct
Choice
True
X
False
Feedback when correct: Correct
Feedback when incorrect: Incorrect