111. Maximum energy loss in a boiler occurs due to _______________________?
A. unburnt carbon in ash
B. incomplete combustion
C. ash content
D. flue gases
E. radiation losses

112. A supercritical boiler is one that operates above the pressure and temperature of following values_____________________?
A. 100 kg/cm2 and 540°C
B. 1 kg/cm2 and 100°C
C. 218 kg/cm2 abs and 373°C
D. 218 kg/cm2 abs and 540°C
E. 100 kg/cm2 abs and 373°C

113. The steam temperature with increase in load in case of a boiler fitted with radiation super heater________________?
A. increases
B. decreases
C. remains unaffected
D. first increases and then decreases
E. unpredictable

114. The relative heat absorption for successively added equal areas of boiler convection heating surfaces____________________?
A. increases
B. decreases
C. remains unaffected
D. first increases and then decreases
E. first decreases and then increases

115. Fire tube boilers are limited to a maximum design working pressure of ____________________?
A. 1 kg/cm
B. 6 kg/cm
C. 17 kg/cm2
D. 100 kg/cm2
E. 250 kg/cm2

116. For combustion of a fuel, following is essential_____________________?
A. correct fuel air ratio
B. proper ignition temperature
C. 02 to support combustion
D. all the three above
E. none of the above

117. The economizer is used in boilers to _______________________?
A. increase thermal efficiency of boiler
B. economise on fuel
C. extract heat from the exhaust flue gases
D. increase flue gas temperature
E. to heat feed water by bled steam

118. 02 content in atmospheric air on volume basis is___________________?
A. 21%
B. 23%
D. 30%
D. 40%
E. 70%

119. Primary air is the air used to__________________?
A. provide air around burners for obtaining optimum combustion
B. transport and dry the coal
C. convert CO (formed in lower zone of furnace) into C02 at higher zone
D. air-delivered by forced draft fan
E. none ot the above

120. Presence of moisture in fuel oil would____________________?
A. keep the burner tips cool
B. aid in proper combustion
C. cause sputtering, possibly extinguish¬ing flame
D. clean the nozzles
E. reduce flame length

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