AMPP CP3 — Cathodic Protection Technologist
Exam Corrosion Theory, CP Design, Anodes,
Rectifiers, Surveys, Interference & Coatings
Actual Questions with Answers
AMPP CP3 – Cathodic Protection Technologist Practice Exam
Verified Questions & Answers with Detailed Rationales (2026/2027 Update)
SECTION 1: CORROSION FUNDAMENTALS & ELECTROCHEMISTRY
1. Corrosion of steel is fundamentally which type of reaction?
A) Mechanical fatigue only
B) Electrochemical reactions involving anodic and cathodic sites
C) Thermal expansion differences
D) Magnetic field variations
Correct Answer: B. Electrochemical reactions involving anodic and cathodic sites.
Rationale: Corrosion is an electrochemical process involving oxidation (loss of
electrons) at anodic locations and reduction (consumption of electrons) at
cathodic locations. An electrolyte enables ionic current flow between these sites .
2. Which of the following are the four required components of an
electrochemical corrosion cell?
A) Anode, cathode, electrolyte, and metallic path
B) Anode, cathode, resistor, and insulator
,C) Cathode, electrolyte, insulator, and power source
D) Electrolyte, metallic path, insulator, and anode
Correct Answer: A. Anode, cathode, electrolyte, and metallic path. Rationale: A
complete corrosion cell requires four components: an anode (where oxidation
occurs), a cathode (where reduction occurs), an electrolyte (for ionic conduction),
and a metallic path (for electron flow). Without any one of these elements, the
corrosion cell cannot function .
3. The anodic reaction in the corrosion of iron is represented by:
A) O₂ + 2H₂O + 4e⁻ → 4OH⁻
B) Fe → Fe²⁺ + 2e⁻
C) 2H⁺ + 2e⁻ → H₂
D) Fe²⁺ + 2e⁻ → Fe
Correct Answer: B. Fe → Fe²⁺ + 2e⁻. Rationale: At the anode, the metal undergoes
oxidation, losing electrons. For iron, the anodic reaction is Fe → Fe²⁺ + 2e⁻. The
cathodic reaction consumes electrons (e.g., O₂ + 2H₂O + 4e⁻ → 4OH⁻) .
4. The cathodic reaction in an aerobic corrosion cell is:
A) Fe → Fe²⁺ + 2e⁻
B) O₂ + 2H₂O + 4e⁻ → 4OH⁻
C) 2H⁺ + 2e⁻ → H₂
D) Fe²⁺ + 2e⁻ → Fe
Correct Answer: B. O₂ + 2H₂O + 4e⁻ → 4OH⁻. Rationale: In aerobic conditions, the
cathodic reaction is oxygen reduction: O₂ + 2H₂O + 4e⁻ → 4OH⁻. This reaction
consumes electrons at the cathode .
5. Which metal would function as the anode in a galvanic couple between
aluminum and steel?
,A) Aluminum
B) Steel
C) Both corrode equally
D) Neither (both are passive)
Correct Answer: A. Aluminum. Rationale: Aluminum is more active (anodic) than
steel in the galvanic series. When coupled, aluminum corrodes preferentially,
protecting the steel (cathode) .
6. Passivation is the process by which a metal:
A) Accelerates its corrosion rate
B) Becomes completely inert to all chemical attack
C) Forms a protective oxide layer that reduces further corrosion
D) Becomes more active in the galvanic series
Correct Answer: C. Forms a protective oxide layer that reduces further corrosion.
Rationale: Passivation occurs when a metal forms a thin, adherent oxide film that
acts as a barrier, significantly reducing further corrosion. Stainless steel is a
common example .
7. Which parameter directly relates the Gibbs free energy change (ΔG) to the cell
potential (E) for a corrosion cell?
A) Faraday's constant
B) Nernst equation
C) ΔG = -nFE
D) Tafel slope
Correct Answer: C. ΔG = -nFE. Rationale: The fundamental thermodynamic
relationship is ΔG = -nFE, where n is the number of electrons transferred and F is
Faraday's constant .
, 8. What is the fundamental driving force for corrosion?
A) Potential difference between electrochemical areas
B) Pipe thickness alone
C) Metal temperature only
D) Atmospheric pressure
Correct Answer: A. Potential difference between electrochemical areas.
Rationale: Differences in electrochemical potential can establish anodic and
cathodic areas and drive corrosion current .
9. Which of the following metals is most susceptible to corrosion in a neutral soil
environment?
A) Titanium
B) Carbon steel
C) Aluminum
D) Stainless steel
Correct Answer: B. Carbon steel. Rationale: Carbon steel is prone to corrosion in
neutral and slightly acidic soils, while metals like titanium and aluminum have
higher corrosion resistance .
10. Which particles travel through a metallic conductor in a conventional CP
circuit?
A) Ions only
B) Electrons
C) Protons
D) Neutrons
Correct Answer: B. Electrons. Rationale: Electrons move through metallic
conductors, while ionic current flows through the electrolyte .
Exam Corrosion Theory, CP Design, Anodes,
Rectifiers, Surveys, Interference & Coatings
Actual Questions with Answers
AMPP CP3 – Cathodic Protection Technologist Practice Exam
Verified Questions & Answers with Detailed Rationales (2026/2027 Update)
SECTION 1: CORROSION FUNDAMENTALS & ELECTROCHEMISTRY
1. Corrosion of steel is fundamentally which type of reaction?
A) Mechanical fatigue only
B) Electrochemical reactions involving anodic and cathodic sites
C) Thermal expansion differences
D) Magnetic field variations
Correct Answer: B. Electrochemical reactions involving anodic and cathodic sites.
Rationale: Corrosion is an electrochemical process involving oxidation (loss of
electrons) at anodic locations and reduction (consumption of electrons) at
cathodic locations. An electrolyte enables ionic current flow between these sites .
2. Which of the following are the four required components of an
electrochemical corrosion cell?
A) Anode, cathode, electrolyte, and metallic path
B) Anode, cathode, resistor, and insulator
,C) Cathode, electrolyte, insulator, and power source
D) Electrolyte, metallic path, insulator, and anode
Correct Answer: A. Anode, cathode, electrolyte, and metallic path. Rationale: A
complete corrosion cell requires four components: an anode (where oxidation
occurs), a cathode (where reduction occurs), an electrolyte (for ionic conduction),
and a metallic path (for electron flow). Without any one of these elements, the
corrosion cell cannot function .
3. The anodic reaction in the corrosion of iron is represented by:
A) O₂ + 2H₂O + 4e⁻ → 4OH⁻
B) Fe → Fe²⁺ + 2e⁻
C) 2H⁺ + 2e⁻ → H₂
D) Fe²⁺ + 2e⁻ → Fe
Correct Answer: B. Fe → Fe²⁺ + 2e⁻. Rationale: At the anode, the metal undergoes
oxidation, losing electrons. For iron, the anodic reaction is Fe → Fe²⁺ + 2e⁻. The
cathodic reaction consumes electrons (e.g., O₂ + 2H₂O + 4e⁻ → 4OH⁻) .
4. The cathodic reaction in an aerobic corrosion cell is:
A) Fe → Fe²⁺ + 2e⁻
B) O₂ + 2H₂O + 4e⁻ → 4OH⁻
C) 2H⁺ + 2e⁻ → H₂
D) Fe²⁺ + 2e⁻ → Fe
Correct Answer: B. O₂ + 2H₂O + 4e⁻ → 4OH⁻. Rationale: In aerobic conditions, the
cathodic reaction is oxygen reduction: O₂ + 2H₂O + 4e⁻ → 4OH⁻. This reaction
consumes electrons at the cathode .
5. Which metal would function as the anode in a galvanic couple between
aluminum and steel?
,A) Aluminum
B) Steel
C) Both corrode equally
D) Neither (both are passive)
Correct Answer: A. Aluminum. Rationale: Aluminum is more active (anodic) than
steel in the galvanic series. When coupled, aluminum corrodes preferentially,
protecting the steel (cathode) .
6. Passivation is the process by which a metal:
A) Accelerates its corrosion rate
B) Becomes completely inert to all chemical attack
C) Forms a protective oxide layer that reduces further corrosion
D) Becomes more active in the galvanic series
Correct Answer: C. Forms a protective oxide layer that reduces further corrosion.
Rationale: Passivation occurs when a metal forms a thin, adherent oxide film that
acts as a barrier, significantly reducing further corrosion. Stainless steel is a
common example .
7. Which parameter directly relates the Gibbs free energy change (ΔG) to the cell
potential (E) for a corrosion cell?
A) Faraday's constant
B) Nernst equation
C) ΔG = -nFE
D) Tafel slope
Correct Answer: C. ΔG = -nFE. Rationale: The fundamental thermodynamic
relationship is ΔG = -nFE, where n is the number of electrons transferred and F is
Faraday's constant .
, 8. What is the fundamental driving force for corrosion?
A) Potential difference between electrochemical areas
B) Pipe thickness alone
C) Metal temperature only
D) Atmospheric pressure
Correct Answer: A. Potential difference between electrochemical areas.
Rationale: Differences in electrochemical potential can establish anodic and
cathodic areas and drive corrosion current .
9. Which of the following metals is most susceptible to corrosion in a neutral soil
environment?
A) Titanium
B) Carbon steel
C) Aluminum
D) Stainless steel
Correct Answer: B. Carbon steel. Rationale: Carbon steel is prone to corrosion in
neutral and slightly acidic soils, while metals like titanium and aluminum have
higher corrosion resistance .
10. Which particles travel through a metallic conductor in a conventional CP
circuit?
A) Ions only
B) Electrons
C) Protons
D) Neutrons
Correct Answer: B. Electrons. Rationale: Electrons move through metallic
conductors, while ionic current flows through the electrolyte .
