steam boilers engines nozzles and turbines MCQs – Page 9

Practise focused steam boilers engines nozzles and turbines questions with marked answers for exam preparation and subject revision.

steam boilers engines nozzles and turbines Mcqs

161. Secondary air is the used to_________________?
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A. convert CO (formed in lower zone of furnace) into C02 at higher zone

B. air delivered by induced draft fan

C. air fed to pulverisers

D. transport and dry the coal

E. provide air around burners for obtaining optimum combustion

162. Thermal efficiency of well maintained boiler will be of the order___________________?
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A. 40%

B. 50%

C. 20%

D. 75%

E. 90%

163. Thermal efficiency of a thermal power plant is of the order of___________________?
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A. 60%.

B. 20%

C. 30%

D. 15%

E. 45%

164. For the same diameter and thickness of tube, a water tube boiler compared to a fire tube boiler has ____________________?
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A. heating surface depends on other parameters

B. equal heating surface

C. less heating surface

D. more heating surface

E. none of the above

165. Reheating of steam under ideal conditions takes place at constant __________________?
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A. enthaply

B. temperature

C. all of the above

D. entropy

E. pressure

166. In forced circulation type boiler__________________?
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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. feed pump is employed to supplement natural circulation in water wall type furnace

C. water is converted into steam in one pass without any recirculation

D. water is heated in a large number of tubes

E. water is supplied in drum and through down-comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam

167. During storage, the heating value of coal __________________?
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A. increases

B. may increase or decrease depending upon the method of storage

C. none of the above

D. decreases

E. remains constant

168. Water at pressure of 4 kg/cm2 and 160C temperature when exposed to atmosphere will_________________?
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A. remain as it was

B. cool down

C. none of the above

D. flash i.e. get converted into steam

E. boil

169. The ultimate analysis of fuel lists _____________________?
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A. moisture and ash free heating value

B. fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash

C. various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as per-cents by volume

D. various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight

E. fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash

170. At which pressure the properties of water and steam become identical_________________?
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A. 225.6 kg/cm2

B. 1 kg/cm2

C. 100 kg/cm2

D. 0.1 kg/cm2

E. it is never possible

171. Steam in water tube boiler as compared to fire tube boiler_________________?
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A. can be raised rapidly

B. is raised at same rate

C. none of the above is true

D. could be raised at fast/slow rate depending on design

E. is raisd at slower rate

172. The proximate analysis of fuel lists__________________?
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A. various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as per-cents by volume

B. moisture and ash free heating value

C. fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash

D. various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight

E. fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash

173. The maximum discharge through a chimney occurs when the height of chimney is_____________________?
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A. equal to the height of the hot gas column producing draught

B. outside temperature is very low

C. more than the tallest building nearby

D. around 200 meters

E. infinitely long

174. The fusible plug in small boilers is located ________________?
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A. over the combustion chamber

B. in the drum

C. above steam dome

D. at the inlet of chimney

E. in the fire tubes

175. The height of chimney in a power plant is governed by__________________?
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A. quantity of flue gases to be handled

B. limitation of construction facilities

C. all of the above

D. the draft to be created

E. control of pollution

176. Caking coals are those which __________________________?
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A. do not form ash

B. form lumps or masses of coke

C. burn completely

D. burn freely

E. show little or no fusing action

177. The safety valve at superheater as compared to drum safety valve setting is set at___________________?
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A. same value

B. lower value

C. any value

D. higher value

E. none of the above

178. Sulphur content of fuels is very important to the plant operators because it____________________?
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A. facilitates ash removal

B. promotes complete combustion

C. has high heating value

D. has highly corrosive effect

E. retards electric precipitation

179. Maximum energy loss in a boiler occurs due to _______________________?
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A. radiation losses

B. ash content

C. unburnt carbon in ash

D. flue gases

E. incomplete combustion

180. On Millier chart, the constant pressure lines_________________?
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A. diverge from right to left

B. none of the above

C. are equally spaced throughout

D. diverge from left to right

E. first rise up and then fall

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Showing 161 to 180 of 194 mcqs