31. The discharge through a converging-diverging nozzle reaches its maximum value when the flow becomes


(a) Sonic at the exit

(b) Sonic at the throat

(c) Supersonic at the throat

(d) Subsonic at the throat

Answer: (b)

32. The speed of a reaction turbine is 250 rpm when working under a head of 120 𝑚. The speed of the turbine when the head is changed to 90 𝑚 will be

(a) 167 rpm

(b) 197 rpm

(c) 217 rpm

(d) 237 rpm

Answer: (c)

33. Consider the following statements regarding reciprocating pump:

1. Frictional losses are maximum at the middle of the stroke

2. Maximum inertia effect occurs in place with zero frictional losses

3. Negative slip may occur when the delivery head is high

Which of the above statements are correct?

(a) 1, 2 and 3

(b) 1 and 3 only

(c) 2 and 3 only

(d) 1 and 2 only

Answer: (d)

34. ‘Shockless entry’ of water in hydraulic turbines is of much significance from the standpoint of

(a) Hydraulic efficiency

(b) Mechanical efficiency

(c) Both hydraulic efficiency and mechanical efficiency

(d) Neither hydraulic efficiency nor mechanical efficiency

Answer: (a)

35. Statement (I): Non viscous flow between two plates is an example for irrotational flow.

Statement (II): Forced vortex is irrotational in nature.

(a) Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)

(b)Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)

(c)Statement (I) is true but Statement (II) is false

(d)Statement (I) is false but Statement (II) is true

Answer: (c)

36. 

(a) Pelton

(b) Kaplan

(c) Francis

(d) Turgo

Answer: (c)

37. Consider the following statements:

1. The specific speed of a two stage centrifugal pump is twice that of a single stage pump

2. The specific speed of a double end suction pump is half that of a single end suction pump

3. The specific speed is not a dimensionless number

Which of the above statements are correct?

(a) 1, 2 and 3

(b) 1 only

(c) 2 only

(d) 3 only

Answer: (c)

38. The fusible plug of a boiler is an example of

(a) Safe life approach

(b) Fail safe approach

(c) Reliability approach

(d) Maintainability approach

Answer: (b)

39. Consider the following statements:

1. The head produced in the primary of a fluid coupling is more than the corresponding centrifugal head

2. When the two speeds are equal, the torque transmitted is zero

Which of the above statements is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer: (c)

40. Consider the following statements:

1. For a given power, a fire tube boiler occupies less space than a water tube boiler,

2. Steam at a high pressure and in large quantities can be produced with a simple vertical boiler

3. A simple vertical boiler has a fire tube

Which of the above statements is/are correct?

(a) 1 only

(b) 2 only

(c) 3 only

(d) 1, 2 and 3

Answer: (c)