131. The discharge is __________ at critical pressure.
[A]. zero
[B]. minimum
[C]. maximum
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✅ The correct answer is option C.
Steam Nozzles and Turbines MCQs
132. The ratio of the workdone on the blades to the energy supplied to the blades, is called
[A]. blading efficiency
[B]. nozzle efficiency
[C]. gross or stage efficiency
[D]. mechanical efficiency
✅ The correct answer is option A.
133. The difference of supersaturated temperature and saturation temperature at that pressure is called
[A]. degree of supersaturation
[B]. degree of superheat
[C]. degree of undercooling
[D]. none of these
✅ The correct answer is option C.
134. Steam turbines are used for
[A]. large marine propulsion
[B]. electric power generation
[C]. direct drive of fans, compressors, pumps
[D]. all of these
✅ The correct answer is option D.
135. The supersaturated flow of steam through a nozzle as compared to a stable flow, the available heat drop
[A]. remains the same
[B]. increases
[C]. decreases
[D]. is unpredictable
✅ The correct answer is option C.
136. The reheat factor is the ratio of the
[A]. cumulative heat drop to the isentropic heat drop
[B]. isentropic heat drop to the heat supplied
[C]. total useful heat drop to the total isentropic heat drop
[D]. none of the above
✅ The correct answer is option A.
137. The critical pressure ratio for initially dry saturated steam is more as compared to initially wet steam.
[A]. Yes
[B]. No
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✅ The correct answer is option B.
138. In a De-Laval nozzle expanding superheated steam from 10 bar to 0.1 bar, the pressure at the minimum cross-section (i. e. pressure at throat, p2) will be
[A]. 3.3 bar
[B]. 5.46 bar
[C]. 8.2 bar
[D]. 9.9 bar
✅ The correct answer is option B.
139. The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle)
[A]. V = 44.72 hd K
[B]. V = 44.72 K hd
[C]. V = 44.72 K hd
[D]. V = 44.72 K hd
✅ The correct answer is option C.
140. The critical pressure ratio for initially wet steam is
[A]. 0.546
[B]. 0.577
[C]. 0.582
[D]. 0.601
✅ The correct answer is option C.