141. A hydraulic coupling belongs to the category of
[A]. power absorbing machines
[B]. power developing machines
[C]. energy transfer machines
[D]. energy generating machines
✅ The correct answer is option C.
Hydraulic Machines MCQs
142. The discharge of a double acting reciprocating pump is (where L = Length of stroke, A = Cross-sectional area of piston, and N = Speed of crank in r.p.m.)
[A]. L.A.N
[B]. 2 L.A.N
[C].
[D].
✅ The correct answer is option D.
143. The speed of a turbine runner is
[A]. directly proportional to H1/2
[B]. inversely proportional to H1/2
[C]. directly proportional to H3/2
[D]. inversely proportional to H3/2
✅ The correct answer is option A.
144. The breast water wheels are those in which the wheel runs partly by the weight of water and partly by the impulse of water.
[A]. True
[B]. False
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✅ The correct answer is option A.
145. The efficiency of a Pelton wheel working under constant head __________ with the increase in power.
[A]. remains same
[B]. increases
[C]. decreases
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✅ The correct answer is option B.
146. The efficiency of a centrifugal pump will be maximum when the blades are bent backward.
[A]. Yes
[B]. No
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✅ The correct answer is option A.
147. The discharge of a centrifugal pump working under constant head __________ with the speed.
[A]. increases
[B]. decreases
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✅ The correct answer is option A.
148. In the casing of a centrifugal pump, the kinetic energy of the water is converted into pressure energy before the water leaves the casing.
[A]. True
[B]. False
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✅ The correct answer is option A.
149. The specific speed of a centrifugal pump, delivering 750 litres of water per second against a head of 15 metres at 725 r.p.m., is
[A]. 24.8 r.p.m.
[B]. 48.2 r.p.m
[C]. 82.4 r.p.m.
[D]. 248 r.p.m
✅ The correct answer is option C.
150. The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, is
[A]. 40%
[B]. 50%
[C]. 60%
[D]. 80%
✅ The correct answer is option B.