Multiple Choice Questions and Answers (MCQs) on Steam Boilers, Engines, Nozzles and Turbines
01. Steam turbines are used for
(A) Large marine propulsion
(B) Electric power generation
(C) Direct drive of fans, compressors, pumps
(D) All of these
Answer: Option D
02. Locomotive boiler is of the following type
(A) Multi tubular
(B) Horizontal
(C) Internally fired
(D) All of the above
Answer: Option D
03. The maximum heat loss is a boiler occurs due to
(A) Moisture in fuel
(B) Dry flue gases
(C) Steam formation
(D) Unburnt carbon
Answer: Option B
04. A single stage impulse turbine with a diameter of 1.2 m runs at 3000 r.p.m. If the blade speed ratio is 0.42, then the inlet velocity of steam will be
(A) 79 m/s
(B) 188 m/s
(C) 450 m/s
(D) 900 m/s
Answer: Option C
05. The actual vacuum in a condenser is equal to
(A) Barometric pressure + actual pressure
(B) Barometric pressure – actual pressure
(C) Gauge pressure + atmospheric pressure
(D) Gauge pressure – atmospheric pressure
Answer: Option B
06. It is required to produce large amount of steam at low pressure. Which boiler should be used?
(A) Pulverised fuel fired boiler
(B) Cochran boiler
(C) Lancashire boiler
(D) Babcock and Wilcox boiler
Answer: Option C
07. Reheating of steam in a turbine
(A) Increases the workdone through the turbine
(B) Increases the efficiency of the turbine
(C) Reduces wear on the blades
(D) All of these
Answer: Option D
08. The ratio of heat actually used in producing the steam to the heat liberated in the furnace, is known as
(A) Equivalent evaporation
(B) Factor of evaporation
(C) Boiler efficiency
(D) Power of a boiler
Answer: Option C
09. In designing air preheaters, the important design consideration is that
(A) Approach temperature should be as low as possible
(B) Handling and maintenance should be easier
(C) Heat transfer area should be optimum
(D) Stack gases should not be cooled to the dew point
Answer: Option D
10. A steam nozzle converts
(A) Heat energy of steam into kinetic energy
(B) Kinetic energy into heat energy of steam
(C) Heat energy of steam into potential energy
(D) Potential energy into heat energy of steam
Answer: Option A
11. The number of water level indicators in a boiler are generally _________ in number.
(A) One
(B) Two
(C) Three
(D) Four
Answer: Option B
12. The maximum discharge through a chimney occurs when the height of chimney is
(A) Infinitely long
(B) Around 200 meters
(C) Equal to the height of the hot gas column producing draught
(D) Outside temperature is very low
Answer: Option C
13. The factor of evaporation for all boilers is always
(A) Equal to unity
(B) Less than unity
(C) Greater than unity
(D) None of these
Answer: Option C
14. Water and sediment in fuel oil can be removed by
(A) Heating the oil in the settling tanks
(B) Cooling the oil in the settling tanks
(C) Burning the oil
(D) Suspension
Answer: Option A
15. For a Parson’s reaction turbine, if α₁ and α₂ are fixed blade angles at inlet and exit respectively and β₁ and β₂ are the moving blade angles at entrance and exit respectively, then
(A) α₁ = α₂ and β₁ = β₂
(B) α₁ = β₁ and α₂= β₂
(C) α₁ < β₁ and α₂ > β₂
(D) α₁ = β₂ and β₁ = α₂
Answer: Option B
16. In a reaction turbine when the degree of reaction is zero, then there is
(A) No heat drop in moving blades
(B) No heat drop in fixed blades
(C) Maximum heat drop in moving blades
(D) Maximum heat drop in fixed blades
Answer: Option A
17. A vessel into which the steam is exhausted and condensed after doing work in an engine cylinder or turbine is known as
(A) Steam condenser
(B) Steam boiler
(C) Steam preheater
(D) Economiser
Answer: Option A
18. The capacity of induced draft fan compared to forced draft fan in a boiler is
(A) Same
(B) More
(C) Less
(D) Less or more depending on size of boiler
Answer: Option B
19. The expansion of steam in a nozzle follows
(A) Carnot cycle
(B) Rankine cycle
(C) Joule cycle
(D) Stirling cycle
Answer: Option B
20. Which of the following compound steam engine requires a smaller flywheel?
(A) Receiver type
(B) Tandem type
(C) Woolf type
(D) All of these
Answer: Option A
21. The feed check valve is used in order to
(A) Regulate flow of boiler water
(B) Check level of water in boiler drum
(C) Recirculate unwanted feed water
(D) Allow high pressure feed water to flow to drum and not allow reverse flow to take place
Answer: Option D
22. The discharge of steam in a convergent-divergent nozzle __________ after the throat (i.e. in the divergent portion of the nozzle)
(A) Remains constant
(B) Decreases
(C) Increases
(D) None of these
Answer: Option A
23. An economiser _________ the steam raising capacity of a boiler.
(A) Increases
(B) Decreases
(C) Has no effect on
(D) None of these
Answer: Option A
24. 1 kg.m is equal to
(A) 9.81 Joules
(B) 102 Joules
(C) 427 Joules
(D) None of these
Answer: Option A
25. When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be
(A) Choked
(B) Under-damping
(C) Over-damping
(D) None of these
Answer: Option B