Steam Boilers, Engines, Nozzles & Turbines 1000+ MCQ with answer for LIC ADO

1. Which of the following varieties of coals is mostly used in steam boilers?
A. Non-coking bituminous coal
B. Brown coal
C. Peat
D. None of the above
Answer : D

2. In a Tandem type compound engine, the high pressure and low pressure cylinders
A. Have common piston rod
B. Are set at 90°
C. Have separate piston rods
D. Are set in V-arrangement
Answer : A

3. Lancashire boiler is
A. Stationary fire tube boiler
B. Internally fired boiler
C. Horizontal boiler
D. All of these
Answer : D

4. The function of an eccentric rod is
A. To provide reciprocating motion to the slide valve
B. To convert reciprocating motion of the piston into rotary motion of the crank
C. To convert rotary motion of the crankshaft into to and fro motion of the valve rod
D. To provide simple harmonic motion to the D-slide valve
Answer : C

5. The compounding of turbines is done in order to
A. Reduce speed of rotor
B. Improve efficiency
C. Reduce exit losses
D. All of these
Answer : D

6. The high pressure and low pressure cylinders in a Woolf type compound engine are regarded as having cranks
A. 180° to each other
B. 90° to each other
C. 0° to each other
D. None of these
Answer : A

7. A fusible plug is fitted in small boilers in order to
A. Avoid excessive build up of pressure
B. Avoid explosion
C. Extinguish fire if water level in the boiler falls below alarming limit
D. Control steam dome
Answer : C

8. In a throttling process
A. Steam temperature remains constant
B. Steam pressure remains constant
C. Steam enthalpy remains constant
D. Steam entropy remains constant
Answer : C

9. The shell of the Cochran boiler is made hemispherical
A. To give maximum space and strength
B. To withstand the pressure of steam inside the boiler
C. Both (A) and (B)
D. None of the above
Answer : C

10. 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 : D

11. A safety valve usually employed with stationary boilers is
A. Lever safety valve
B. Dead weight safety valve
C. High steam and low water safety valve
D. All of these
Answer : D

12. Duplex feed pumps are used in small steam boilers. These operate on the principle of
A. Centrifugal pump
B. Axial flow pump
C. Gear pump
D. Reciprocating pump
Answer : D

13. Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler
A. Increases
B. Decreases
C. Remain unaffected
D. First increases and then decreases
Answer : B

14. Cut-off governing as compared to throttle governing is
A. Less efficient and less economical
B. Less efficient and more economical
C. More efficient and less economical
D. More efficient and more economical
Answer : D

15. For maximum discharge through a chimney, the condition is that height of hot gas column producing the draught should be
A. One-half the height of chimney
B. Equal to the height of chimney
C. Two times the height of chimney
D. Four times the height of chimney
Answer : B

16. The radius of a dished head is taken approximately as
A. One fourth
B. Half
C. One
D. Two
Answer : C

17. The shell diameter of a Locomotive boiler is
A. 1 m
B. 1.5 m
C. 2 m
D. 2.5 m
Answer : B

18. Which of the following gases has the highest calorific value?
A. Producer gas
B. Coal gas
C. Water gas
D. Blast furnace gas
Answer : B

19. The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be
A. 0.4
B. 0.56
C. 0.67
D. 1.67
Answer : A

20. The ratio of brake power to the indicated power is known as
A. Mechanical efficiency
B. Overall efficiency
C. Indicated thermal efficiency
D. Brake thermal efficiency
Answer : A

21. The clearance in the engine cylinder
A. Increases the mean effective pressure
B. Increases the workdone
C. Decreases the efficiency of the engine
D. All of these
Answer : D

22. In a boiler, feed water supplied per hour is 205 kg while coal fired per hour is 23 kg. The net enthalpy rise per kg of water is 145 kJ. If the calorific valve of the coal is 2050 kJ/kg, then the boiler efficiency will be
A. 56 %
B. 63 %
C. 74 %
D. 78 %
Answer : B

23. Ultimate analysis of fuel is determination of percentage of
A. Carbon, hydrogen, nitrogen, sulphur, moisture
B. Fixed carbon, ash, volatile matter, moisture
C. Higher calorific value
D. Lower calorific value
Answer : A

24. The fire tubes in a Scotch marine boiler are
A. Horizontal
B. Vertical
C. Inclined
D. None of these
Answer : A

25. The high pressure and low pressure cylinders in a Tandem type compound engine are regarded as having cranks
A. 180° to each other
B. 90° to each other
C. 0° to each other
D. None of these
Answer : C

26. The aim of a compound steam engine is
A. To reduce the ratio of expansion in each cylinder
B. To reduce the length of stroke
C. To reduce the temperature range in each cylinder
D. All of the above
Answer : D

27. 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 : A

28. In a boiler, the heat is lost
A. To dry flue gases
B. In moisture present in the fuel
C. To steam formed by combustion of hydrogen per kg of fuel
D. All of the above
Answer : D

29. All steam engines work on
A. Zeroth law of thermodynamics
B. First law of thermodynamics
C. Second law of thermodynamics
D. None of these
Answer : C

30. The pressure velocity compounded impulse turbine allows a bigger pressure drop and hence __________ numbers of stages are required.
A. More
B. Less
C. Equal
D. None of these
Answer : B

31. Hard coke is used in
A. Cement industry
B. Thermal power plant
C. Blast furnace
D. Domestic use
Answer : C

32. A double acting steam engine with a cylinder diameter of 190 mm and a stroke of 300 mm has a cut-off of 0.35. The expansion ratio for this engine is nearly
A. 1.05
B. 2.86
C. 6.65
D. 10.05
Answer : B

33. The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and h_d = Enthalpy or heat drop during expansion of steam in a nozzle)
A. V = 44.72 h_d K
B. V = 44.72 K h_d
C. V = 44.72 K h_d
D. V = 44.72 K h_d
Answer : C

34. A compound steam engine in which piston rods of high pressure and low pressure cylinders are attached to two different cranks set at 90° to each other, is called
A. Receiver type compound engine
B. Tandem type compound engine
C. Woolf type compound engine
D. Both (A) and (B)
Answer : A

35. Which of the following statement is correct?
A. Lancashire boiler is a fire tube boiler.
B. Fire tube boilers are internally fired.
C. Babcock and Wilcox boiler is a water tube boiler.
D. All of the above
Answer : D

36. A compound steam engine in which piston rods of high pressure and low pressure cylinders ' are attached to two different cranks set at 180° to each other, is called
A. Receiver type compound engine
B. Tandem type compound engine
C. Woolf type compound engine
D. Both (A) and (B)
Answer : C

37. The behaviour of coal in a furnace is determined by
A. The content of sulphur
B. The content of ash and heating value
C. The proximate analysis
D. The exact analysis
Answer : C

38. Adiabatic process is
A. Essentially an isentropic process
B. Non-heat transfer process
C. Reversible process
D. Constant temperature process
Answer : B

39. An air preheater is installed
A. Before the economiser
B. Before the superheater
C. Between the economiser and chimney
D. None of these
Answer : C

40. The fire tubes in a Cochran boiler usually have _________ diameter.
A. 6.25 mm
B. 62.5 mm
C. 72.5 mm
D. 92.5 mm
Answer : B

41. One kg of steam sample contains 0.8 kg dry steam; Its dryness fraction is
A. 0.2
B. 0.8
C. 1.0
D. 0.6
Answer : B

42. An economiser in a boiler
A. Increases steam pressure
B. Increases steam flow
C. Decreases fuel consumption
D. Decreases steam pressure
Answer : C

43. A compound steam engine in which the high pressure and low pressure cylinders have common piston rod, is called
A. Receiver type compound engine
B. Tandem type compound engine
C. Woolf type compound engine
D. None of these
Answer : B

44. When the circulation of water, in a boiler, is by a centrifugal pump, then the boiler is known as
A. Internally fired boiler
B. Externally fired boiler
C. Natural circulation boiler
D. Forced circulation boiler
Answer : D

45. The Locomotive boiler has
A. 137 fire tubes and 44 superheated tubes
B. 147 fire tubes and 34 superheated tubes
C. 157 fire tubes and 24 superheated tubes
D. 167 fire tubes and 14 superheated tubes
Answer : C

46. The temperature of flue gases at air heater outlet should be
A. 100°C
B. Above dew point temperature of flue gases
C. Below dew point temperature of flue gases
D. Less than wet bulb temperature of flue gases
Answer : B

47. The critical pressure ratio for gases is
A. 0.528
B. 0.546
C. 0.577
D. 0.582
Answer : A

48. The ratio of the workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam is called
A. Blading efficiency
B. Nozzle efficiency
C. Stage efficiency
D. Mechanical efficiency
Answer : C

49. The number of flue tubes in Lancashire boiler is
A. Zero
B. One
C. Two
D. Four
Answer : C

50. Water tube boilers are
A. Internally fired
B. Externally fired
C. Internally as well as externally fired
D. None of these
Answer : B