# Practice Test: Question Set - 03

1. Specific speed for reaction turbines ranges from
(A) 0 to 4.5
(B) 10 to 100
(C) 80 to 200
(D) 250 to 300

2. The efficiency of jet propulsion for a ship with inlet orifices at right angles to the direction of motion of ship is given by
(A) [2(Vr - v) v]/ Vr²
(B) [2(Vr + v) v]/ Vr²
(C) [(Vr - v) v]/ Vr
(D) [(Vr + v) v]/ Vr

3. Air vessels in reciprocating pump are used to
(A) Smoothen flow
(B) Reduce acceleration to minimum
(C) Increase pump efficiency
(D) Save pump from cavitations

4. For 450 m head of water, _________ shall be used.
(A) Pelton wheel
(B) Kaplan turbine
(C) Francis turbine
(D) None of these

5. According to fan laws, for fans having constant wheel diameter, the air or gas capacity varies
(A) Directly as fan speed
(B) Square of fan speed
(C) Cube of fan speed
(D) Square root of fan speed

6. The speed ratio in case of Francis turbine varies from
(A) 0.15 to 0.3
(B) 0.4 to 0.5
(C) 0.6 to 0.9
(D) 1 to 1.5

7. The specific speed of turbine is defined as the speed of a unit
(A) Of such a size that it delivers unit discharge at unit head
(B) Of such a size that it delivers unit discharge at unit power
(C) Of such a size that it requires unit power per unit head
(D) Of such a size that it produces unit horse power with unit head

8. The undershot water wheels are those in which
(A) The wheel runs entirely by the weight of water
(B) The wheel runs entirely by the impulse of water
(C) The wheel runs partly by the weight of water and partly by the impulse of water
(D) None of the above

9. Guide angle as per the aerofoil theory of Kaplan turbine blade design is defined as the angle between
(A) Lift and resultant force
(B) Drag and resultant force
(C) Lift and tangential force
(D) Lift and drag

10. In an outward flow reaction turbine
(A) The water flows parallel to the axis of the wheel
(B) The water enters at the centre of the wheel and then flows towards the outer periphery of the wheel
(C) The water enters the wheel at the outer periphery and then flows towards the centre of the wheel
(D) The flow of water is partly radial and partly axial

11. Impulse turbine is generally fitted
(A) At the level of tail race
(B) Little above the tail race
(C) Slightly below the tail race
(D) About 2.5 m above the tail race to avoid cavitations

12. The gross or total head of the turbine is the ___________ of the water levels at the head race and tail race.
(A) Sum
(B) Difference
(C) Product
(D) None of these

13. In axial flow fans and turbines, fluid enters and leaves as follows
(C) Axially, axially

14. Which of the following statement is correct?
(A) In an impulse turbine, the water impinges on the buckets with pressure energy.
(B) In a reaction turbine, the water glides over the moving vanes with kinetic energy.
(C) In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure.
(D) In a reaction turbine, the pressure of the flowing water increases after gliding over the vanes.

15. According to fan laws, for fans having constant wheel diameter, the pressure varies
(A) Directly as fan speed
(B) Square of fan speed
(C) Cube of fan speed
(D) Square root of fan speed

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