# Hydraulic Machines-Fluid Machineries – Set 09

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## Q1. The total pressure force on a plane area is equal to the area multiplied by the intensity of pressure at the Centroid, if

(A) The area is horizontal
(B) The area is vertical
(C) The area is inclined
(D) All of the above

Answer: (D) All of the above

(A) 100 cm3
(B) 250 cm3
(C) 500 cm3
(D) 1000 cm3

## Q3. Pressure of the order of 10″ torr can be measured by

(A) Bourdon tube
(B) Pirani Gauge
(C) Micro-manometer
(D) Lonisation gauge

## Q4. The value of bulk modulus of a fluid is required to determine

(A) Reynold’s number
(B) Froude’s number
(C) Mach number
(D) Euler’s number

## Q5. Flow of water in a pipe about 3 meters in diameter can be measured by

(A) Orifice plate
(B) Venturimeter
(C) Rotameter
(D) Pitot tube

## Q6. Metacentre is the point of intersection of

(A) Vertical upward force through e.g. of body and center line of body
(B) Buoyant force and the center line of body
(C) Midpoint between e.g. and center of buoyancy
(D) All of the above

Answer: (B) Buoyant force and the center line of body

## Q7. The discharge through a wholly drowned orifice is given by (where H1 = Height of water (on the upstream side) above the top of the orifice, H2 = Height of water (on the downstream side) above the bottom of the orifice, and H = Difference between two water levels on either side of the orifice)

(A) Q = Cd × bH₁ × √(2gh)
(B) Q = Cd × bH2 × √(2gh)
(C) Q = Cd × b (H2 – H1) × √(2gh)
(D) Q = Cd × bH × √(2gh)

Answer: (C) Q = Cd × b (H2 – H1) × √(2gh)

## Q8. Froude number is significant in

(A) Supersonics, as with projectile and jet propulsion
(B) Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
(C) Simultaneous motion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect, as with ship’s hulls
(D) All of the above

Answer: (C) Simultaneous motion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect, as with ship’s hulls

## Q9. A manometer is used to measure

(A) Atmospheric pressure
(B) Pressure in pipes and channels
(C) Pressure in Venturimeter
(D) Difference of pressures between two points in a pipe

Answer: (B) Pressure in pipes and channels

(A) 1000 kg
(B) 4000 kg
(C) 2000 kg
(D) 8000 kg

## Q11. The discharge over a right angled notch is (where H = Height of liquid above the apex of notch)

(A) (8/15) Cd. 2g. H
(B) (8/15) Cd. 2g. H3/2
(C) (8/15) Cd. 2g. H²
(D) (8/15) Cd. 2g. H5/2

## Q12. Steady flow occurs when

(A) The direction and magnitude of the velocity at all points are identical
(B) The velocity of successive fluid particles, at any point, is the same at successive periods of time
(C) The magnitude and direction of the velocity do not change from point to point in the fluid
(D) The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane

Answer: (B) The velocity of successive fluid particles, at any point, is the same at successive periods of time

## Q13. An opening in the side of a tank or vessel such that the liquid surface with the tank is below the top edge of the opening, is called

(A) Weir
(B) Notch
(C) Orifice
(D) None of these

## Q14. The surface tension of mercury at normal temperature compared to that of water is

(A) More
(B) Less
(C) Same
(D) More or less depending on size of glass tube

## Q15. According to Bernoulli’s equation

(A) Z + p/w + v²/2g = constant
(B) Z + p/w – v²/2g = constant
(C) Z – p/w + v²/2g = constant
(D) Z – p/w – v²/2g = constant

Answer: (A) Z + p/w + v²/2g = constant

## Q16. The tendency of a liquid surface to contract is due to the following property

(A) Cohesion
(C) Viscosity
(D) Surface tension

(B) h²
(C) V/T
(D) h/2

## Q18. The power absorbed (in watts) in overcoming the viscous resistance of a footstep bearing is

(A) μ π³ N² R² /1800 t
(B) μ π³ N² R⁴ /1800 t
(C) μ π³ N² R² /3600 t
(D) μ π³ N² R⁴ /3600 t

Answer: (B) μ π³ N² R⁴ /1800 t

## Q19. A balloon lifting in air follows the following principle

(A) Law of gravitation
(B) Archimedes principle
(C) Principle of buoyancy
(D) All of the above