MCQs on Power Systems

Page 54 of 67. Go to page
01․ Which of the following is an impulse turbine
Pelton turbine.
Francis turbine.
Kaplan turbine.
None of above.

In impulse turbines all available energy of water is converted into KE.

02․ Which of the following is a reaction turbines
Pelton turbine and Francis turbine.
Francis turbine and Kaplan turbine.
Kaplan and Pelton turbine.
None of these.

In reaction turbines at entrance to the runner only a part of available energy of water is converted into k.e and substantial path remains in the form of pressure energy.

03․ Alternate formation and breakage of bubbles are called
water hamming.
all of the above.

Mostly cavitation takes place in reaction turbines. This will decrease the efficiency of turbines and cause severe damage of turbine.

04․ Water hamming process in pen-stocks results in
noise increases.
pressure increases.
noise increases, pressure increases, velocity decreases.
none of the above.

Due to sudden closer of valve velocity of fluid decreases, pressure of fluid is increases. Hence some noise will produce this phenomenon is called water hammer.

05․ A hydro electric generating station is supplied from a reservoir of capacity 5 × 10 − 6 cubic meters at a head of 200 meters. Find the total energy available in KWh if the overall efficiency is 75 %
2.044 × 106 kWh.
3 × 106 kWh.
4.06 × 106 kWh.
5 × 106 kWh.

Weight of water available is W = volume of water × density = 5 × 106 × 1000 = 5 × 109 = 5 × 109 × 9.81 N. \

06․ For harnessing low variable water heads, the suitable hydraulic turbine with high percentage of reaction and runner adjust vanes is

Kaplan is used for run-of-river and poundage stations with heads of up to 61 m ( low head ). This type has an a axial flow rotor with variable pitch blades.

07․ A hydraulic turbine having rated speed of 250 rpm is connected to a synchronous generator. In order to produce power at 50 Hz, the numbers of pole are required in the generator


08․ For large plants of capacity for more than 15 MW, what type of cooling is used

Hydrogen cooling reduces windage losses, provides better cooling, reduces oxidation of insulation and also reduces fire hazards. So it is most suitable for large capacity plants.

09․ How much KWh energy is produced by fission of 1 gm of uranium U235
24 kWh.
240 kWh.
2400 kWh.
24000 kWh.

24000 KWh of amount of heat energy is produced by fission of 1 gm of uranium U235.

10․ Among the following which is not non conventional energy

Nuclear energy is considered as conventional energy source along with coal, oil, natural gas. Nuclear elements are the source of nuclear energy.