steam boilers engines nozzles and turbines MCQs – Page 7

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

121. Sulphur in coal results in___________________?
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A. corroding air heaters

B. all of the above

C. causing clinkering and slagging

D. spontaneous combustion during coal storage

E. facilitating ash precipitation

122. The latent heat of steam with increase of pressure__________________?
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A. increases

B. none of the above

C. remains same

D. behaves unpredictably

E. decreases

123. Spontaneous combustion is a phenomenon in which____________________?
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A. all the fuel burns instantaneously producing high energy release

B. none of the above

C. explosion in furnace

D. fuel burns with less air

E. coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal

124. Which is not correct statement about the function of furnace____________________?
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A. to provide proper conditions for con-tinuous complete combustion

B. separate ash from coal

C. mix fuel with air and ignite

D. maintain heat supply to prepare and ignite the incoming fuel

E. to minimise radiation losses

125. For combustion of a fuel, following is essential_____________________?
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A. none of the above

B. all the three above

C. proper ignition temperature

D. 02 to support combustion

E. correct fuel air ratio

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

B. 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

C. heating of water takes place in stages

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

E. 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

127. In regenerative air preheater, the heat is transferred _____________________?
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A. from heating an intermediateanaterial and then heating the air from this material

B. none of the above

C. by direct mixing

D. from a metal wall from one medium to another

E. heat is transferred by bleeding some gas from furnace

128. In locomotives, the draught is produced by_________________?
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A. chimney

B. induced draft fan

C. both combined A. and B.

D. steam jet draught

E. none of the above

129. The bituminous coal is non-caking if its carbon content is_______________?
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A. 85-90%

B. 78-81%

C. 81-85%

D. 95-100%.

E. 90-95%

130. Size of boiler tubes is specified by___________________?
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A. outside diameter and inside diameter

B. outside diameter and thickness

C. inside diameter and thickness

D. mean diameter and thickness

E. outside diameter alone

131. The pressure of reheat steam after passing through reheater compared to inlet condition is _________________?
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A. equal

B. more

C. may be more or less depending on capacity of reheater

D. less

E. none of the above

132. Green coal, in order to be burnt, must be____________________?
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A. burnt in excess air

B. burnt as lumps

C. heated to its ignition point

D. burnt as powder

E. heated sufficiently

133. The basic job of feed water treatment in boilers is to overcome the problem of __________________?
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A. corrosion

B. carryover

C. scale

D. embrittlement

E. all of the above

134. The diameter of fire tubes in Cochran boiler is of the order of___________________?
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A. 2 cm

B. 15 cm

C. 12 cm

D. 6 Cm ,

E. 8 cm

135. The temperature of flue gases at air heater outlet should be__________________?
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A. 100C

B. above dew-point temperature of flue gases

C. above wet bulb temperature of flue gases

D. less than wet bulb temperature of flue gases

E. below dew-point temperature of flue gases

136. Boiler H.P. is defined as the ________________ ?
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A. the evaporation of 15.65 kg of water per hour from and at 100C into dry saturated steam

B. heat consumed in evaporating 1 kg water at 0C to steam at 100C and 1.033 kg/cm pressure

C. steam evaporation rate per kg of fuel fired

D. work done by 1 kg of steam at saturation condition

E. work done in evaporating 1 kg of steam per hour from and at 100C into dry saturated steam

137. The steam temperature with increase in load in case of a boiler fitted with radiation super heater________________?
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A. unpredictable

B. first increases and then decreases

C. decreases

D. increases

E. remains unaffected

138. Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler _________________?
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A. increases

B. decreases

C. first decreases and then increases

D. remains unaffected

E. first increases and then decreases

139. The economizer is used in boilers to _______________________?
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A. extract heat from the exhaust flue gases

B. increase flue gas temperature

C. increase thermal efficiency of boiler

D. to heat feed water by bled steam

E. economise on fuel

140. Bomb calorimeter is used to determine ___________________?
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A. Lower calorific value at constant volume ,

B. Lower calorific value at constant pressure

C. Higher calorific value at constant volume

D. Higher calorific value at constant pressure

E. None of the above

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Showing 121 to 140 of 194 mcqs