78. The diameter of internal flue tubes in a Lancashire boiler compared to its shell is
A.One-half
B.Two-fifth.
C.One-fourth
D.One-fifth

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79. The basic purpose of drum in boiler is to
A.Serve as storage of steam
B.Serve as storage of feed water for water wall
C.Remove salts from water
D.Separate steam from water

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80. Duplex feed pumps are used in small steam boilers. These operate on the principle of
A.Centrifugal pump
B.Reciprocating pump.
C.Gear pump
D.Ejector pump

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81. The best suited coal for chain or travelling grate stoker boiler is
A.Coking coal
B.Non coking or free burning coal
C.Pulverised coal
D.High sulphur coal

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82. In natural circulation type boiler
A.Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
B.Water is supplied in durm, and through down-comers located in atmospheric conditon it passes to the water wall and rises to drum in the form of mixture of water and steam
C.Feed pump is employed to supplement natural circulation in water wall type furnace
D.Water is converted into steam in one pass without any recirculation

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83. Hard coke is produced by carborisation of coal at
A.Atmospheric temperature
B.500-600°C
C.700-850°C
D.950-1100°C

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

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