Questions and answers for exam Preparation

MCQs

Total Questions : 304 | Page 7 of 31 pages

Question 61. Slip of a reciprocating pump is defined as the

ratio of actual discharge to the theoretical discharge
sum of actual discharge and the theoretical discharge
difference of theoretical discharge and the actual discharge
product of theoretical discharge and the actual discharge

Discuss Question

Answer: Option C. -> difference of theoretical discharge and the actual discharge
Answer: (c).difference of theoretical discharge and the actual discharge

Question 62. Multi-stage centrifugal pumps are used to

give high discharge
produce high heads
pump viscous fluids
all of these

Discuss Question

Answer: Option B. -> produce high heads
Answer: (b).produce high heads

Question 63. The efficiency of a centrifugal pump will be maximum when the blades are bent backward.

Yes
No
Can't say
None of these

Discuss Question

Answer: Option A. -> Yes
Answer: (a).Yes

Question 64. Theoretical power required (in watts) to drive a reciprocating pump is (where w = Specific weight of liquid to be pumped in N/m³, Q = Discharge of the pump in m³/s, Hs = Suction head in metres, and Hd = Delivery head in metres)

wQHs
wQHd
wQ(Hs - Hd)
wQ(Hs + Hd)

Discuss Question

Answer: Option D. -> wQ(Hs + Hd)
Answer: (d).wQ(Hs + Hd)

Question 65. 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

24.8 r.p.m.
48.2 r.p.m
82.4 r.p.m.
248 r.p.m

Discuss Question

Answer: Option C. -> 82.4 r.p.m.
Answer: (c).82.4 r.p.m.

Question 66. A draft tube is used with impulse turbines.

Yes
No
Can't say
None of these

Discuss Question

Answer: Option B. -> No
Answer: (b).No

Question 67. A hydraulic ram is a device used to

store the energy of water
increase the pressure of water
to lift water from deep wells
to lift small quantity of water to a greater height when a large quantity of water is available at a smaller height

Discuss Question

Answer: Option D. -> to lift small quantity of water to a greater height when a large quantity of water is available at a smaller height
Answer: (d).to lift small quantity of water to a greater height when a large quantity of water is available at a smaller height

Question 68. The function of guide vanes in a reaction turbine is to

allow the water to enter the runner without shock
allow the water to flow over them, without forming eddies
allow the required quantity of water to enter the turbine
all of the above

Discuss Question

Answer: Option D. -> all of the above
Answer: (d).all of the above

Question 69. Overall efficiency of a centrifugal pump is the ratio of

energy available at the impeller to the energy supplied to the pump by the prime mover
actual workdone by the pump to the energy supplied to the pump by the prime mover
energy supplied to the pump to the energy available at the impeller
manometric head to the energy supplied by the impeller per kN of water

Discuss Question

Answer: Option B. -> actual workdone by the pump to the energy supplied to the pump by the prime mover
Answer: (b).actual workdone by the pump to the energy supplied to the pump by the prime mover

Question 70. Which of the following statement is correct ?

In an impulse turbine, the water impinges on the buckets with pressure energy.
In a reaction turbine, the water glides over the moving vanes with kinetic energy.
In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure.
In a reaction turbine, the pressure of the flowing water increases after gliding over the vanes.

Discuss Question

Answer: Option C. -> In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure.
Answer: (c).In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure.