30.

31.

32.

33.

84,

35.

36.

87.

If the area included within 450 m, 453 m and 456 m contour lines of a reservoir are
respectively 250 sq.m and 750 sq.m, the volume of water (by trapezoidal formula) will be :

(^) 450000 cu.m (B) 225000 cum
(C) 1000 cum (D) 1500 cu.m

A jet of water strikes a flat plate with a velocity of 20 m/s inclined at 30° with the axis of the
jet. If the cross-sectional area of the jet is 50cm”and density of water is 1000 kg/cu.m, the
force exerted by the jet on the plane will be :

(മ 1732.05N (B) 866.002 7
(C) 500N (D) 1000 N
For maximum efficiency of the vanes, the peripheral speed should be :
(4) 1/4% of the velocity of jet (B) Half of the velocity of jet
(C) Equal to the jet speed (D) 0.6 times jet speed

A jet propelled boat moves at 20 m/s with water being drawn from inlet openings facing the
direction of motion. If the relative velocity of the jet is found to be 30 m/s, its propulsion
efficiency will be :

(ಸ) 80% ൫ 57.14%
©) 40% D 4%

‘Which of the following statement is INCORRECT?
(ക) Modern Francis turbines are inward mixed flow reaction turbines

(B) Francis turbines operates under medium heads and requires medium quantity ‏اه‎
‎water

(©) The head acting on the Francis turbine is fully transformed into kinetic energy
leaving no pressure head

(D) In Francis turbine, the difference of pressure between the guide vanes and the
runner creates the reaction pressure

A turbine is to operate under a head of 16 m at 128 rpm. If the power generated is 625 kW,
the specific speed of the turbine will be :

(4) 400 rpm (3) 2500 rpm
(C) 100 rpm (D) None of the above

The impeller of a centrifugal pump has an internal diameter of 400 mm and it runs at
720 rpm. If the constant radial flow through impeller is 1.51m/s, the inlet vane angle will be :

മ) 185° 42 “ (®) 95° 42
(0 45" D) 5°42

The phenomenon of cavitation in centrifugal pumps can be reduced by :
(^) Reducing the suction head (3) Increasing the suction head
(C) Altering the flow velocity (D) Changing the discharge -

7 142/2015
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