1. Which of the following types of pump can be used for concreting?

- Centrifugally operated with straight blades
- Pneumatically operated

- ii only
- i only
- Neither i nor ii
- Both i and ii

2. Which of the following statement is correct?

- centrifugal pumps convert mechanical energy into hydraulic energy by sucking liquid chamber
- reciprocating pumps convert mechanical energy into hydraulic energy by means of centrifugal energy
- centrifugal pumps convert mechanical energy into hydraulic energy by means of centrifugal energy
- reciprocating pumps convert hydraulic energy into mechanical energy

3. In a centrifugal pump, the inlet angle will be designed to have

- absolute velocity vector in the radial direction
- zero flow velocity
- relative velocity vector in the radial direction
- zero peripheral velocity

4. In order to avoid cavitation in centrifugal pumps

- the suction pressure should be high
- the delivery pressure should be high
- the suction pressure should be low
- the delivery pressure should be low

5. In a centrifugal pump pressure energy is developed due to

- Displacement
- Whirling Motion
- Both whirling and displacement
- None of the above

6. In a centrifugal pump the liquid enters the pump

- at the centre
- at the top
- at the bottom
- from sides

7. A centrifugal pump delivers water at the rate of 40 lit/s for a total head of 30 m. If the overall efficiency of set consists of pump and electric motor is 75%, the power required to drive the motor is

- 12.4 kW
- 13.8 kW
- 15.7 kW
- 14.3 kW

8. In centrifugal pumps, the relation between power (P) and speed (N) is given by

- P ∝ N
- P ∝ N
^{2} - P ∝ N
^{3} - None of these

9. For centrifugal pump impeller, the maximum value of the vane exit angle is

- 10° to 15°
- 15° to 20°
- 20° to 25°
- 25° to 30°

10. Multistage centrifugal pumps are used to velocity

- give high discharge
- pump viscous fluids
- produce high heads
- both a and c

11. A diffuser blade in the centrifugal pump is used to

- convert mechanical energy to kinetic energy
- convert kinetic energy to pressure energy
- convert pressure energy to kinetic energy
- convert potential energy to kinetic energy

12. Which one is not centrifugal pump?

- Volute
- Diffuser
- Reciprocating
- Turbine

13. Rotadynamic pump is classified as

- Centrifugal pumps
- Screw pumps
- Propeller pumps

Which of these statements are correct?

- Only i and iii
- Only i and ii
- All three
- Only ii and iii

14. The discharge from a centrifugal pump is 100 lpm and the leakage is 11 lpm. Then the volumetric efficiency of the pump is

- 89%
- 90%
- 99%
- 80%

15. A centrifugal pump driven by a directly coupled 3 kW motor of 1450 rpm speed is proposed to be connected to another motor of 2900 rpm. The power of the motor should be

- 24 kW
- 18 kW
- 12 kW
- 6 kW

16. The size of centrifugal water pump is given by

- Horsepower
- Impeller diameter
- Discharge
- Suction and delivery pipe diameter

17. When speed changes in case of centrifugal pump, which of the following points are correct?

- The shape of the velocity triangle will remain same
- Various angles will remain same
- Magnitude of velocity will change proportionately

- i and ii only
- i and iii only
- ii and iii only
- i, ii and iii

18. Which one of the following statements is correct regarding centrifugal pumps?

- The discharge is fluctuating and pulsating
- It is used for large discharge through smaller heads
- The efficiency is low
- It runs at low speed

19. Of the following statements, pick the correct one.

- Centrifugal pumps are used to produce high head
- Centrifugal pumps are used to discharge large quantity of water

- Statement (ii) alone is correct
- Both the statement are wrong
- Statement (i) alone is correct
- Both the statements are correct

20. A centrifugal pump has an impeller of 30cm diameter and runs at 1000 rpm giving best efficiency. It delivered 1.2 m^{3}/minute against a head of 25m. What is its non-dimensional specific speed (based on flow expressed in l.p.s.)?

- 80
- 72
- 63
- 55