SSC JE Exam - pumps turbines measurement of flow Question Bank with Options

1. The maximum theoretical efficiency of a Pelton turbine is limited by:

A) Friction losses

B) Air resistance

C) The fact that the bucket cannot completely reverse the jet's direction

D) Cavitation

2. Which flow measurement device measures the velocity of fluid by detecting the frequency of reflected sound waves?

A) Turbine flow meter

B) Doppler ultrasonic flow meter

C) Electromagnetic flow meter

D) Venturimeter

3. A 'critical depth' is a concept primarily associated with:

A) Pump operation

B) Turbine design

C) Open channel flow

D) Pipe flow measurement

4. The 'specific speed' of a pump is defined as the speed at which it would run to deliver:

A) Unit head at unit discharge

B) Unit discharge at unit head

C) Unit power at unit head

D) Unit head at unit power

5. Which type of turbine is characterized by adjustable guide vanes and a propeller-like runner?

A) Pelton turbine

B) Francis turbine

C) Kaplan turbine

D) Cross-flow turbine

6. The characteristic curve of a pump plots:

A) Discharge vs. speed

B) Head vs. discharge

C) Power vs. discharge

D) Efficiency vs. head

7. A multistage centrifugal pump is used to achieve:

A) Higher discharge

B) Higher head

C) Lower power consumption

D) Improved efficiency at low flow

8. The overall efficiency of a pump is the product of:

A) Mechanical efficiency and volumetric efficiency

B) Hydraulic efficiency and mechanical efficiency

C) Hydraulic efficiency, mechanical efficiency, and volumetric efficiency

D) Volumetric efficiency and power efficiency

9. Which flow measurement device requires a conductive fluid to operate?

A) Orifice plate

B) Venturimeter

C) Electromagnetic flow meter

D) Rotameter

10. The 'vena contracta' is the point of:

A) Maximum velocity in a Venturimeter

B) Minimum cross-sectional area of a jet after leaving a nozzle or orifice

C) Maximum pressure in an orifice meter

D) Lowest flow rate in a weir

11. A 'weir' is primarily used for measuring:

A) Flow rate in a closed pipe

B) Water level in a tank

C) Flow rate in an open channel

D) Pressure in a fluid

12. What is the function of a governor in a hydraulic power plant?

A) To control the flow of water to the turbine

B) To regulate the speed of the turbine

C) To measure the power output

D) To prevent cavitation

13. In a Francis turbine, the water flows:

A) Radially outwards

B) Axially through the runner

C) Radially inwards and then axially

D) Tangentially to the runner

14. The 'runner' is the rotating component of a:

A) Pump

B) Turbine

C) Both pump and turbine

D) Flow meter

15. Which of the following is a characteristic of a centrifugal pump?

A) Constant discharge flow rate regardless of head

B) Discharge varies with head

C) Requires priming before starting

D) Operates on the principle of trapping fluid

16. The phenomenon of 'water hammer' in a pipeline is caused by:

A) Sudden closure of a valve

B) Excessive pump speed

C) Low fluid viscosity

D) High friction losses

17. A 'sump' in a pumping system is typically:

A) The discharge pipe

B) The source of fluid from which the pump draws water

C) The power supply to the pump

D) The mechanism for priming the pump

18. For a given head, the discharge of a Pelton turbine is primarily controlled by the:

A) Speed of rotation

B) Size of the buckets

C) Number of nozzles

D) Needle valve opening

19. The 'breakdown torque' in a turbine refers to:

A) The torque at which the turbine starts rotating

B) The maximum torque the turbine can withstand without damage

C) The torque at which the turbine stops delivering useful power

D) The torque developed at rated speed

20. Which component of a reaction turbine guides the water onto the runner and controls the flow rate?

A) Draft tube

B) Runner

C) Guide vanes

D) Shaft

21. The maximum efficiency of a centrifugal pump is usually achieved when the impeller is:

A) Operating at its maximum speed

B) Operating at its minimum speed

C) Operating at its best efficiency point (BEP)

D) Operating at shut-off head

22. A positive displacement pump traps a fixed amount of fluid and forces (displaces) it into the discharge pipe.

A) True

B) False

C) Only for liquids

D) Only for gases

23. What is the primary advantage of using an ultrasonic flow meter?

A) Low cost

B) Ability to measure flow in dirty or corrosive fluids

C) Simple installation

D) High accuracy at very low flow rates

24. The coefficient of discharge for an orifice meter is typically:

A) Greater than 1

B) Equal to 1

C) Less than 1

D) Varies with fluid density

25. In a flow measurement using a Venturimeter, the pressure difference is measured between the:

A) Throat and the outlet

B) Inlet and the outlet

C) Inlet and the throat

D) Diverging section and the outlet

26. Which of the following is NOT a type of flow measurement device?

A) Manometer

B) Weir

C) Venturimeter

D) Orifice plate

27. The efficiency of a turbine is defined as the ratio of:

A) Shaft power to water power

B) Water power to shaft power

C) Hydraulic power to shaft power

D) Shaft power to hydraulic power

28. A Kaplan turbine is particularly suitable for:

A) High head, low discharge

B) Medium head, medium discharge

C) Low head, high discharge

D) Very high head, low discharge

29. Which parameter is used to characterize the performance of a turbine under varying head and speed?

A) Specific speed

B) Runaway speed

C) Operating speed

D) Rated speed

30. The shut-off head of a centrifugal pump is:

A) The head at which the pump delivers zero discharge

B) The maximum head the pump can deliver

C) The head at which the pump operates at its best efficiency

D) The head required to overcome friction in the discharge pipe

31. What is the purpose of a foot valve in a suction pipe of a centrifugal pump?

A) To regulate the flow

B) To prevent backflow and keep the pipe full of water

C) To increase the suction head

D) To reduce priming time

32. The 'head' in a pump refers to:

A) The power input to the pump

B) The difference in pressure energy between the suction and discharge sides

C) The total energy difference, including pressure, velocity, and elevation, between the suction and discharge sides

D) The rotational speed of the impeller

33. Which type of turbine operates with the water jet striking buckets on the periphery of the runner?

A) Francis turbine

B) Kaplan turbine

C) Pelton turbine

D) Turgo turbine

34. The operation of an electromagnetic flow meter is based on:

A) Bernoulli's principle

B) Faraday's law of electromagnetic induction

C) The Doppler effect

D) The principle of buoyancy

35. Which device uses a float that rises and falls with the liquid level to indicate flow rate?

A) Ultrasonic flow meter

B) Electromagnetic flow meter

C) Rotameter

D) Turbine flow meter

36. What is the main advantage of a V-notch weir over a rectangular weir for measuring flow?

A) It can handle higher flow rates

B) It is more accurate for low flow rates

C) It requires less head

D) It is easier to construct

37. The discharge over a rectangular weir is proportional to:

A) H^1.5

B) H^2.5

C) H^3.5

D) H^0.5

38. A Pitot tube is primarily used to measure:

A) Average velocity

B) Static pressure

C) Stagnation pressure

D) Velocity at a point

39. Which flow measurement device consists of a converging section, a throat, and a diverging section?

A) Orifice plate

B) Flow nozzle

C) Venturimeter

D) Pitot tube

40. The principle behind the operation of an orifice meter is:

A) Bernoulli's equation

B) Torricelli's theorem

C) Archimedes' principle

D) Pascal's law

41. A Venturimeter is used to measure:

A) Pressure

B) Velocity

C) Flow rate in a pipe

D) Water level

42. Which of the following is a common method for measuring flow rate in an open channel?

A) Venturimeter

B) Orifice plate

C) Weir

D) Rotameter

43. What is the 'specific speed' of a turbine?

A) The speed of the turbine at which it runs without any load

B) The speed of the turbine at which it develops a unit power

C) The speed of the turbine at which it develops a unit head

D) The speed of the turbine at which it runs at maximum efficiency

44. The main purpose of a draft tube in a reaction turbine is to:

A) Increase the speed of the water leaving the turbine

B) Recover the kinetic energy of the water leaving the runner

C) Reduce the pressure at the turbine outlet

D) Guide the water towards the penstock

45. Which turbine is best suited for high head and low discharge applications?

A) Kaplan turbine

B) Francis turbine

C) Pelton turbine

D) Propeller turbine

46. A Francis turbine is a type of:

A) Impulse turbine

B) Reaction turbine

C) Pelton turbine

D) Cross-flow turbine

47. Cavitation in a centrifugal pump occurs when:

A) The fluid temperature is too high

B) The static pressure at the impeller eye drops below the vapor pressure of the liquid

C) The discharge valve is fully closed

D) The pump speed is too low

48. What is the primary function of a volute casing in a centrifugal pump?

A) To increase the speed of the fluid

B) To convert kinetic energy into pressure energy

C) To reduce the friction losses

D) To guide the fluid into the impeller

49. The efficiency of a centrifugal pump is generally highest at:

A) Zero discharge

B) Maximum discharge

C) Best efficiency point (BEP)

D) Minimum speed

50. Which type of pump is most suitable for handling fluids with high viscosity?

A) Centrifugal pump

B) Submersible pump

C) Positive displacement pump

D) Jet pump

pumps turbines measurement of flow - Question Bank