AMPP Cathodic Protection Technologist
(CP3) Certification Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
Q1. What is the primary purpose of a cathodic protection (CP) system?
A. Increase the tensile strength of the structure
B. Reduce coating thickness requirements
C. Control corrosion by making the protected structure the cathode of an
electrochemical cell
D. Eliminate all electrolytes surrounding the structure
Rationale: Cathodic protection reduces corrosion by shifting the
electrochemical conditions so the protected metal functions as the
cathode, suppressing its anodic dissolution.
,Q2. Which two basic methods are commonly used to provide cathodic
protection?
A. Coating and painting
B. Galvanic anode and impressed current
C. Insulation and grounding
D. Passivation and heat treatment
Rationale: CP systems generally use either sacrificial/galvanic anodes or
externally powered impressed-current systems.
Q3. In an impressed-current cathodic protection system, the DC power
source is typically called a:
A. Transformer
B. Rectifier
C. Rectifier/transformer unit
D. Reference electrode
Rationale: An impressed-current system commonly uses a transformer-
rectifier to convert and regulate AC power into suitable DC output.
,Q4. What is the fundamental electrochemical reaction associated with
corrosion of iron at an anodic site?
A. 2H₂O + O₂ → 4OH⁻
B. Fe²⁺ + 2e⁻ → Fe
C. Fe → Fe²⁺ + 2e⁻
D. 2H⁺ + 2OH⁻ → 2H₂O
Rationale: At an anodic site, iron atoms lose electrons and enter the
electrolyte as ferrous ions.
Q5. Which electrode reaction occurs at a cathodic site in an acidic
environment?
A. Fe → Fe²⁺ + 2e⁻
B. 2H⁺ + 2e⁻ → H₂
C. Zn → Zn²⁺ + 2e⁻
D. Cu → Cu²⁺ + 2e⁻
Rationale: In acidic electrolytes, hydrogen-ion reduction can consume
electrons at the cathode and produce hydrogen gas.
Q6. What is the main function of a reference electrode in CP testing?
, A. Supply CP current
B. Measure anode consumption
C. Provide a stable reference potential for measuring structure-to-
electrolyte potential
D. Increase soil conductivity
Rationale: A reference electrode provides a relatively stable
electrochemical potential against which the structure potential can be
measured.
Q7. Which reference electrode is widely used for CP measurements in soil?
A. Platinum electrode
B. Aluminum electrode
C. Copper/copper sulfate electrode
D. Stainless-steel electrode
Rationale: The copper/copper sulfate reference electrode is commonly
used for measuring buried steel structures in soil.
Q8. What does a structure-to-electrolyte potential measurement indicate?
(CP3) Certification Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
Q1. What is the primary purpose of a cathodic protection (CP) system?
A. Increase the tensile strength of the structure
B. Reduce coating thickness requirements
C. Control corrosion by making the protected structure the cathode of an
electrochemical cell
D. Eliminate all electrolytes surrounding the structure
Rationale: Cathodic protection reduces corrosion by shifting the
electrochemical conditions so the protected metal functions as the
cathode, suppressing its anodic dissolution.
,Q2. Which two basic methods are commonly used to provide cathodic
protection?
A. Coating and painting
B. Galvanic anode and impressed current
C. Insulation and grounding
D. Passivation and heat treatment
Rationale: CP systems generally use either sacrificial/galvanic anodes or
externally powered impressed-current systems.
Q3. In an impressed-current cathodic protection system, the DC power
source is typically called a:
A. Transformer
B. Rectifier
C. Rectifier/transformer unit
D. Reference electrode
Rationale: An impressed-current system commonly uses a transformer-
rectifier to convert and regulate AC power into suitable DC output.
,Q4. What is the fundamental electrochemical reaction associated with
corrosion of iron at an anodic site?
A. 2H₂O + O₂ → 4OH⁻
B. Fe²⁺ + 2e⁻ → Fe
C. Fe → Fe²⁺ + 2e⁻
D. 2H⁺ + 2OH⁻ → 2H₂O
Rationale: At an anodic site, iron atoms lose electrons and enter the
electrolyte as ferrous ions.
Q5. Which electrode reaction occurs at a cathodic site in an acidic
environment?
A. Fe → Fe²⁺ + 2e⁻
B. 2H⁺ + 2e⁻ → H₂
C. Zn → Zn²⁺ + 2e⁻
D. Cu → Cu²⁺ + 2e⁻
Rationale: In acidic electrolytes, hydrogen-ion reduction can consume
electrons at the cathode and produce hydrogen gas.
Q6. What is the main function of a reference electrode in CP testing?
, A. Supply CP current
B. Measure anode consumption
C. Provide a stable reference potential for measuring structure-to-
electrolyte potential
D. Increase soil conductivity
Rationale: A reference electrode provides a relatively stable
electrochemical potential against which the structure potential can be
measured.
Q7. Which reference electrode is widely used for CP measurements in soil?
A. Platinum electrode
B. Aluminum electrode
C. Copper/copper sulfate electrode
D. Stainless-steel electrode
Rationale: The copper/copper sulfate reference electrode is commonly
used for measuring buried steel structures in soil.
Q8. What does a structure-to-electrolyte potential measurement indicate?
