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MD STATIONARY ENGINEER GRADE 1 EXAM 2026-2027
BANK QUESTIONS WITH DETAILED VERIFIED ANSWERS
EXAM QUESTIONS WILL COME FROM HERE (100%
CORRECT ANSWERS A+ GRADED
1. In a watertube boiler, circulation is primarily achieved by the
difference in density between:
A) Feedwater and condensate
B) Steam and water in the downcomer and riser tubes
C) Saturated steam and superheated steam
D) Water in the mud drum and steam drum
Answer: B
Explanation: Natural circulation in a watertube boiler relies on the
thermosiphon effect. Water in the downcomers is cooler and denser,
while the water-steam mixture in the risers is hotter and less dense.
This density differential creates a pressure head that drives circulation.
2. The primary function of a superheater in a steam power plant is to:
A) Increase the steam pressure before entering the turbine
B) Remove moisture from saturated steam
C) Increase the temperature of steam above its saturation point
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D) Preheat combustion air using exhaust steam
Answer: C
Explanation: A superheater adds sensible heat to saturated steam,
raising its temperature above the boiling point for a given pressure.
This increases the thermal efficiency of the Rankine cycle and reduces
moisture content in the turbine's later stages, preventing blade erosion.
3. Cavitation in a centrifugal pump is most likely caused by:
A) Discharge valve being closed too far
B) Net Positive Suction Head (NPSH) available being less than NPSH
required
C) Operating the pump at dead head
D) Excessive fluid viscosity
Answer: B
Explanation: Cavitation occurs when the static pressure at the pump
impeller eye falls below the fluid's vapor pressure, forming vapor
bubbles that violently collapse. This happens when NPSH available
(system pressure head) is insufficient to overcome the pump's NPSH
required.
4. The carbon content in medium-carbon steel typically ranges from:
A) 0.05% to 0.15%
B) 0.15% to 0.30%
C) 0.30% to 0.60%
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D) 0.60% to 1.00%
Answer: C
Explanation: Medium-carbon steels contain 0.30% to 0.60% carbon,
balancing ductility with strength and hardness. They respond well to
heat treatment and are used for shafts, gears, and railway tracks,
whereas low-carbon steels are below 0.30% and high-carbon steels
above 0.60%.
5. According to the ideal gas law, if the volume of a confined gas is
halved while temperature remains constant, the pressure will:
A) Remain the same
B) Double
C) Halve
D) Increase by a factor of four
Answer: B
Explanation: Boyle's Law, a derivative of the ideal gas law for isothermal
processes, states P1V1 = P2V2. If V2 = 0.5 V1, then P2 = P1V.5V1 =
2P1. Thus, pressure doubles when volume is halved at constant
temperature.
6. The purpose of a blowdown valve on a boiler is to:
A) Relieve excess steam pressure
B) Drain condensate from the steam main
C) Remove accumulated sludge and control dissolved solids
concentration
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D) Vent air during boiler startup
Answer: C
Explanation: Boiler blowdown removes concentrated dissolved solids
and non-adherent sludge from the boiler water. This prevents
carryover, foaming, and scale formation, maintaining steam purity and
heat transfer efficiency.
7. In a firetube boiler, heat transfer to the water occurs primarily via:
A) Radiation from the flame
B) Convection from hot gases passing through the tubes
C) Conduction through the refractory walls
D) Radiation from the steam space
Answer: B
Explanation: In a firetube boiler, hot combustion gases flow through
submerged tubes. The dominant mode of heat transfer is forced
convection from the hot gases to the tube wall, then conduction
through the wall, and finally convection to the surrounding water.
8. A thermocouple operates based on the principle of:
A) Change in resistance with temperature
B) Thermal expansion of a bimetallic strip
C) Seebeck effect generating a voltage at the junction of two dissimilar
metals
D) Ionization of gas in a flame
MD STATIONARY ENGINEER GRADE 1 EXAM 2026-2027
BANK QUESTIONS WITH DETAILED VERIFIED ANSWERS
EXAM QUESTIONS WILL COME FROM HERE (100%
CORRECT ANSWERS A+ GRADED
1. In a watertube boiler, circulation is primarily achieved by the
difference in density between:
A) Feedwater and condensate
B) Steam and water in the downcomer and riser tubes
C) Saturated steam and superheated steam
D) Water in the mud drum and steam drum
Answer: B
Explanation: Natural circulation in a watertube boiler relies on the
thermosiphon effect. Water in the downcomers is cooler and denser,
while the water-steam mixture in the risers is hotter and less dense.
This density differential creates a pressure head that drives circulation.
2. The primary function of a superheater in a steam power plant is to:
A) Increase the steam pressure before entering the turbine
B) Remove moisture from saturated steam
C) Increase the temperature of steam above its saturation point
,2|Page
D) Preheat combustion air using exhaust steam
Answer: C
Explanation: A superheater adds sensible heat to saturated steam,
raising its temperature above the boiling point for a given pressure.
This increases the thermal efficiency of the Rankine cycle and reduces
moisture content in the turbine's later stages, preventing blade erosion.
3. Cavitation in a centrifugal pump is most likely caused by:
A) Discharge valve being closed too far
B) Net Positive Suction Head (NPSH) available being less than NPSH
required
C) Operating the pump at dead head
D) Excessive fluid viscosity
Answer: B
Explanation: Cavitation occurs when the static pressure at the pump
impeller eye falls below the fluid's vapor pressure, forming vapor
bubbles that violently collapse. This happens when NPSH available
(system pressure head) is insufficient to overcome the pump's NPSH
required.
4. The carbon content in medium-carbon steel typically ranges from:
A) 0.05% to 0.15%
B) 0.15% to 0.30%
C) 0.30% to 0.60%
,3|Page
D) 0.60% to 1.00%
Answer: C
Explanation: Medium-carbon steels contain 0.30% to 0.60% carbon,
balancing ductility with strength and hardness. They respond well to
heat treatment and are used for shafts, gears, and railway tracks,
whereas low-carbon steels are below 0.30% and high-carbon steels
above 0.60%.
5. According to the ideal gas law, if the volume of a confined gas is
halved while temperature remains constant, the pressure will:
A) Remain the same
B) Double
C) Halve
D) Increase by a factor of four
Answer: B
Explanation: Boyle's Law, a derivative of the ideal gas law for isothermal
processes, states P1V1 = P2V2. If V2 = 0.5 V1, then P2 = P1V.5V1 =
2P1. Thus, pressure doubles when volume is halved at constant
temperature.
6. The purpose of a blowdown valve on a boiler is to:
A) Relieve excess steam pressure
B) Drain condensate from the steam main
C) Remove accumulated sludge and control dissolved solids
concentration
, 4|Page
D) Vent air during boiler startup
Answer: C
Explanation: Boiler blowdown removes concentrated dissolved solids
and non-adherent sludge from the boiler water. This prevents
carryover, foaming, and scale formation, maintaining steam purity and
heat transfer efficiency.
7. In a firetube boiler, heat transfer to the water occurs primarily via:
A) Radiation from the flame
B) Convection from hot gases passing through the tubes
C) Conduction through the refractory walls
D) Radiation from the steam space
Answer: B
Explanation: In a firetube boiler, hot combustion gases flow through
submerged tubes. The dominant mode of heat transfer is forced
convection from the hot gases to the tube wall, then conduction
through the wall, and finally convection to the surrounding water.
8. A thermocouple operates based on the principle of:
A) Change in resistance with temperature
B) Thermal expansion of a bimetallic strip
C) Seebeck effect generating a voltage at the junction of two dissimilar
metals
D) Ionization of gas in a flame
