BOILERS 2ND CLASS PRACTICE EXAM PREP
NEWEST 2026/2027 EXAM COMPLETE 60
QUESTIONS AND CORRE
Section A: Boiler Fundamentals & Thermodynamics (Q1–Q12)
• 1. What is the primary purpose of a boiler?
o A. Generate electricity directly
o B. Produce steam or hot water by transferring heat from combustion
to water
o C. Compress air for pneumatic tools
o D. Cool industrial processes
o Correct Answer: B
o Rationale: A boiler is a closed vessel that transfers heat from a
fuel source to water, producing steam or hot water for heating or
process use. It does not generate electricity directly (that is the
turbine/generator), compress air, or cool processes.
• 2. Which thermodynamic cycle best describes a steam power plant?
o A. Otto cycle
o B. Brayton cycle
o C. Rankine cycle
o D. Diesel cycle
o Correct Answer: C
o Rationale: The Rankine cycle is the ideal cycle for steam power
plants, involving pump, boiler, turbine, and condenser. Otto and
Diesel are internal combustion cycles; Brayton is for gas turbines.
,• 3. In a boiler, what does "sensible heat" refer to?
o A. Heat that changes the phase of water
o B. Heat that raises the temperature of water without changing its
phase
o C. Heat lost through the stack
o D. Heat generated by friction
o Correct Answer: B
o Rationale: Sensible heat raises the temperature of a substance
without a phase change. Latent heat is required for phase change
(e.g., boiling water into steam).
• 4. What is the enthalpy of steam?
o A. The pressure of steam at a given temperature
o B. The total heat content of steam, including sensible and latent heat
o C. The volume of steam produced per hour
o D. The velocity of steam in the pipe
o Correct Answer: B
o Rationale: Enthalpy (h) is the total heat energy in steam,
comprising sensible heat in the water plus latent heat of vaporization.
It is expressed in kJ/kg.
• 5. Which of the following is a primary fuel for boilers?
o A. Nitrogen
o B. Natural gas
o C. Oxygen
o D. Carbon dioxide
, o Correct Answer: B
o Rationale: Natural gas is a common boiler fuel. Nitrogen, oxygen,
and carbon dioxide are not fuels; they are components of air or
combustion products.
• 6. What is the function of a superheater in a boiler?
o A. Remove moisture from steam
o B. Add heat to saturated steam to raise its temperature above
saturation
o C. Preheat feedwater
o D. Reduce flue gas temperature
o Correct Answer: B
o Rationale: A superheater adds heat to saturated steam, raising its
temperature above the saturation point, improving efficiency and
reducing condensation in turbines. Moisture removal is done by
separators; feedwater preheating by economizers.
• 7. What is the critical point of water?
o A. 100°C and 1 atm
o B. 374°C and 22.1 MPa
o C. 0°C and 0.006 atm
o D. 200°C and 10 MPa
o Correct Answer: B
o Rationale: The critical point of water is approximately 374°C (647
K) and 22.1 MPa (218 atm), where liquid and vapor phases become
indistinguishable. Above this, no distinct phase change occurs.
• 8. What is "boiler efficiency"?
, o A. Ratio of steam produced to fuel consumed
o B. Ratio of heat output to heat input
o C. Ratio of water consumed to steam produced
o D. Ratio of flue gas temperature to steam temperature
o Correct Answer: B
o Rationale: Boiler efficiency is the ratio of useful heat output
(steam) to heat input (fuel), expressed as a percentage. It measures
how well the boiler converts fuel energy into steam.
• 9. Which instrument measures boiler pressure?
o A. Thermometer
o B. Bourdon tube pressure gauge
o C. Flow meter
o D. Hydrometer
o Correct Answer: B
o Rationale: A Bourdon tube pressure gauge is standard for
measuring boiler pressure. Thermometers measure temperature;
flow meters measure flow; hydrometers measure density.
• 10. What is the purpose of a safety valve on a boiler?
o A. Regulate fuel flow
o B. Release excess pressure to prevent explosion
o C. Drain water from the boiler
o D. Indicate water level
o Correct Answer: B
NEWEST 2026/2027 EXAM COMPLETE 60
QUESTIONS AND CORRE
Section A: Boiler Fundamentals & Thermodynamics (Q1–Q12)
• 1. What is the primary purpose of a boiler?
o A. Generate electricity directly
o B. Produce steam or hot water by transferring heat from combustion
to water
o C. Compress air for pneumatic tools
o D. Cool industrial processes
o Correct Answer: B
o Rationale: A boiler is a closed vessel that transfers heat from a
fuel source to water, producing steam or hot water for heating or
process use. It does not generate electricity directly (that is the
turbine/generator), compress air, or cool processes.
• 2. Which thermodynamic cycle best describes a steam power plant?
o A. Otto cycle
o B. Brayton cycle
o C. Rankine cycle
o D. Diesel cycle
o Correct Answer: C
o Rationale: The Rankine cycle is the ideal cycle for steam power
plants, involving pump, boiler, turbine, and condenser. Otto and
Diesel are internal combustion cycles; Brayton is for gas turbines.
,• 3. In a boiler, what does "sensible heat" refer to?
o A. Heat that changes the phase of water
o B. Heat that raises the temperature of water without changing its
phase
o C. Heat lost through the stack
o D. Heat generated by friction
o Correct Answer: B
o Rationale: Sensible heat raises the temperature of a substance
without a phase change. Latent heat is required for phase change
(e.g., boiling water into steam).
• 4. What is the enthalpy of steam?
o A. The pressure of steam at a given temperature
o B. The total heat content of steam, including sensible and latent heat
o C. The volume of steam produced per hour
o D. The velocity of steam in the pipe
o Correct Answer: B
o Rationale: Enthalpy (h) is the total heat energy in steam,
comprising sensible heat in the water plus latent heat of vaporization.
It is expressed in kJ/kg.
• 5. Which of the following is a primary fuel for boilers?
o A. Nitrogen
o B. Natural gas
o C. Oxygen
o D. Carbon dioxide
, o Correct Answer: B
o Rationale: Natural gas is a common boiler fuel. Nitrogen, oxygen,
and carbon dioxide are not fuels; they are components of air or
combustion products.
• 6. What is the function of a superheater in a boiler?
o A. Remove moisture from steam
o B. Add heat to saturated steam to raise its temperature above
saturation
o C. Preheat feedwater
o D. Reduce flue gas temperature
o Correct Answer: B
o Rationale: A superheater adds heat to saturated steam, raising its
temperature above the saturation point, improving efficiency and
reducing condensation in turbines. Moisture removal is done by
separators; feedwater preheating by economizers.
• 7. What is the critical point of water?
o A. 100°C and 1 atm
o B. 374°C and 22.1 MPa
o C. 0°C and 0.006 atm
o D. 200°C and 10 MPa
o Correct Answer: B
o Rationale: The critical point of water is approximately 374°C (647
K) and 22.1 MPa (218 atm), where liquid and vapor phases become
indistinguishable. Above this, no distinct phase change occurs.
• 8. What is "boiler efficiency"?
, o A. Ratio of steam produced to fuel consumed
o B. Ratio of heat output to heat input
o C. Ratio of water consumed to steam produced
o D. Ratio of flue gas temperature to steam temperature
o Correct Answer: B
o Rationale: Boiler efficiency is the ratio of useful heat output
(steam) to heat input (fuel), expressed as a percentage. It measures
how well the boiler converts fuel energy into steam.
• 9. Which instrument measures boiler pressure?
o A. Thermometer
o B. Bourdon tube pressure gauge
o C. Flow meter
o D. Hydrometer
o Correct Answer: B
o Rationale: A Bourdon tube pressure gauge is standard for
measuring boiler pressure. Thermometers measure temperature;
flow meters measure flow; hydrometers measure density.
• 10. What is the purpose of a safety valve on a boiler?
o A. Regulate fuel flow
o B. Release excess pressure to prevent explosion
o C. Drain water from the boiler
o D. Indicate water level
o Correct Answer: B
