NACE CP2 Quiz 2 Questions and Answers (Verified Answers)|Graded A+
4 views 0 purchase
Course
NACE CP2
Institution
NACE CP2
NACE CP2 Quiz 2 Questions and Answers (Verified Answers)
A structure-to-electrolyte potential measures the potential difference between
A. Two different structures acting as electrodes
B. The structure and a standard reference electrode
C. The structure and the anodes
D. Two different points...
NACE CP2 Quiz 2 Questions and Answers
(Verified Answers)
A structure-to-electrolyte potential measures the potential difference between
A. Two different structures acting as electrodes
B. The structure and a standard reference electrode
C. The structure and the anodes
D. Two different points on the structure
B. The structure and a standard reference electrode
If 5.0 A of battery current passes through the outside leads of a 4-wire current span spaced at 30 m
(100 ft), resulting in a voltage drop of 5.0 mV with the test current applied and of 1 mV without the
test current, what is a the calibration factor of the current span?
A. 0.00025 A/mV
B. 4.0 A/mV
C. 1.25 A/mV
D. 5.0 A/mV
C. 1.25 A/mV
I = 5 A EC = 5 mV ENC = 1 mV
K = I/(EC - ENC) = 5 A/(5 mV - 1 mV) = 1.25 A/mV
Polarized potentials are measured
A. when the rectifiers are ON
B. just after the rectifiers are turned OFF
C. after the rectifiers are left off for several days
D. just after the Rectifiers are turned ON
B. just after the rectifiers are turned OFF
Polarization is determined by
A. Subtracting the ON from the instant OFF potential
B. Measuring the instant OFF potential
C. Subtracting the instant OFF from the Native (free corroding) potential
D. Substracting the IR drop from the ON potential
C. Subtracting the instant OFF from the Native (free corroding) potential
Current pickup on a pipeline is indicated when
A. The structure-to-electrolyte potential over the pipe is more electronegative than each side
B. The structure-to-electrolyte potential over the pipe is more electropositive than each side
C. The two electrode method (side drain) shows the electrode over the pipe is more electropositive
D. A CIS shows a more electropositive potential with the rectifier ON than OFF
B. The structure-to-electrolyte potential over the pipe is more electropositive than each side
A 61 cm diameter (24 in) pipe has a current span at each end of a 2 km (1.24 miles) section with the
following information determined:
EONts1 = -1200 mVcse EONts2 = -1140 mVcse
, EOFFts1 = -1000 mVcse EOFFts2 = -980 mVcse
IONts1 = 3 A IONts2 = 2.8 A
IOFFts1 = 0.2 A IOFFts2 - = 0.2 A
What is the pipe-to-earth resistance (ohm)?
A. 0.9 ohm
B. 9 ohm
C. 66.7 ohm
D. 900 ohm
A. 0.9 ohm
Rc = DeltaE/Ic
Ic = Delta1ts1 - DeltaIts2 = (3 - 0.2) - (2.8 - 0.2)
Ic = 0.2 A
DeltaE = (DeltaEts1 - DeltaEts2)/2
DeltaE = ((1200-1000)+(1140-980))/2 = 180 mV
Rc = 180 mV/0.2 A = 0.9 ohm
A 61 cm diameter (24 in) pipe has a current span at each end of a 2 km (1.24 miles) section with the
following information determined:
EONts1 = -1200 mVcse EONts2 = -1140 mVcse
EOFFts1 = -1000 mVcse EOFFts2 = -980 mVcse
IONts1 = 3 A IONts2 = 2.8 A
IOFFts1 = 0.2 A IOFFts2 - = 0.2 A
What is the specific coating resistance (ohm-m2)?
A. 0.00023 ohm-m2
B. 0.023 ohm-m2
C. 3450 ohm-m2
D. 345000 ohm-m2
C. 3450 ohm-m2
D = 61 cm = 0.61 m L= 2 km = 2000 m
A = piDL = pi(0.61 m)(2000 m) = 3830.8 m2
rCE = A*Rc = (3830.8 m2)(0.9 ohm) = 3447.72 ohm-m2
(Rc from question 6)
A 61 cm diameter (24 in) pipe has a current span at each end of a 2 km (1.24 miles) section with the
following information determined:
EONts1 = -1200 mVcse EONts2 = -1140 mVcse
EOFFts1 = -1000 mVcse EOFFts2 = -980 mVcse
IONts1 = 3 A IONts2 = 2.8 A
IOFFts1 = 0.2 A IOFFts2 - = 0.2 A
What is the specific coating conductance (siemans/m2)?
A. 0.0000029 siemans/m2
B. 0.00029 siemans/m2
C. 43.5 siemans/m2
D. 4347 siemans/m2
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LectDan. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.69. You're not tied to anything after your purchase.
