1).The “specific speed” of a water turbine is the speed at which the turbine develops.
a)
maximum horse power.
maximum horse power.
b)
unit horse power at all heads.
unit horse power at all heads.
c)
unit horse power at unit head.
unit horse power at unit head.
d)
minimum horse power.
minimum horse power.
Answer: c)
The specific speed of the turbines is defined as the speed of a geometrically similar turbine that would develop one metric horse power under a head of one meter.
2).The specific speeds of kaplan, francis and pelton turbines are in.
a)
The increasing order.
The increasing order.
b)
The decreasing order.
The decreasing order.
c)
neither increasing nor decreasing order.
neither increasing nor decreasing order.
d)
none of all.
none of all.
Answer: B)
the specific speed of Kaplan, Francis and pelton turbines are in order of 300 to 1000, 60 to 300 and 10 to 50 in metric units respectively.
3).An impulse turbine.
a)
is most suited for low head and high discharge power plants.
is most suited for low head and high discharge power plants.
b)
operates by initial complete conversion to kinetic energy.
operates by initial complete conversion to kinetic energy.
c)
makes use of a draft tube.
makes use of a draft tube.
d)
always operates submerged.
always operates submerged.
Answer: B) when the entire pressure of water is converted into kinetic energy in nozzle and the jet thus formed drives the wheel, the turbine is called impulse turbine.
4).Turbines installed at Bhakra Nangal are.
a)
pelton wheels.
pelton wheels.
b)
Francis turbines.
Francis turbines.
c)
Kaplan turbines.
Kaplan turbines.
d)
propeller turbines.
propeller turbines.
Answer: A)
5).In water turbines the runaway speed of pelton wheel is.
a)
1.8 times rated speed.
1.8 times rated speed.
b)
2-22 times rated speed.
2-22 times rated speed.
c)
25-3 times rated speed.
25-3 times rated speed.
d)
full load speed.
full load speed.
Answer: A)
6).The number of buckets (Z) for a pelton wheel in terms of jet rati(m) is given by empirical relation.
a)
Z=15 m+0.5.
Z=15 m+0.5.
b)
Z=0.5 m+15.
Z=0.5 m+15.
c)
Z=2 m+15.
Z=2 m+15.
d)
Z=2+15 m.
Z=2+15 m.
Answer: B)
7).In reaction turbine, the function of draft tube is to.
a)
reduce water hammer.
reduce water hammer.
b)
increase flow rate of water.
increase flow rate of water.
c)
convert kinetic energy of water to potential energy by a gradual expansion in divergent pan.
convert kinetic energy of water to potential energy by a gradual expansion in divergent pan.
d)
none of the above.
none of the above.
Answer: C)
8).In Francis turbine of blades is usually of the order of.
a)
16-24.
16-24.
b)
8-10.
8-10.
c)
6-8.
6-8.
d)
3-6.
3-6.
Answer: A)
9).The maximum head of a kaplan turbine is limited to.
a)
25 m.
25 m.
b)
70 m.
70 m.
c)
125 m.
125 m.
d)
185 m.
185 m.
Answer: A)
propellar turbine are reaction turbine which is suitable for low head and large quantity of water. It is mainly suitable for heads below 30m
10).which of the following statements is/are correct, In pumped storage power plants.
a)
water is recirculated through water turbines.
water is recirculated through water turbines.
b)
reversible turbines are used which operate as turbines for
power generation during peak load hours and as pumps for
pumping water during peak-off hours.
reversible turbines are used which operate as turbines for
power generation during peak load hours and as pumps for
pumping water during peak-off hours.
c)
plain Francis turbines are used.
plain Francis turbines are used.
d)
both (a) and (c) above are employed.
both (a) and (c) above are employed.
Answer: B)
