# Hydraulics and Fluid Mechanics MCQ – Set 17

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## Q1. The increase of temperature results in

(A) Increase in viscosity of gas
(B) Increase in viscosity of liquid
(C) Decrease in viscosity of gas
(D) Decrease in viscosity of liquid

Answer: (D) Decrease in viscosity of liquid

## Q2. Liquids transmit pressure equally in all the directions. This is according to

(A) Boyle’s law
(B) Archimedes principle
(C) Pascal’s law
(D) Newton’s formula

(A) Notch
(B) Weir
(C) Mouthpiece
(D) Nozzle

## Q4. Euler’s number is the ratio of __ force to pressure force.

(A) Inertia
(B) Gravity
(C) Viscous
(D) None of these

## Q5. The discharge through a channel of trapezoidal section is maximum when

(A) Width of channel at the top is equal to twice the width at the bottom
(B) Depth of channel is equal to the width at the bottom
(C) The sloping side is equal to half the width at the top
(D) The sloping side is equal to the width at the bottom

Answer: (C) The sloping side is equal to half the width at the top

## Q6. The bulk modulus of elasticity

(A) Has the dimensions of 1/pressure
(B) Increases with pressure
(C) Is large when fluid is more compressible
(D) Is independent of pressure and viscosity

(A) 0.46
(B) 0.64
(C) 0.78
(D) 0.87

(A) p = T × r
(B) p = T/r
(C) p = T/2r
(D) p = 2T/r

(A) v₁²/2g
(B) v₂²/2g
(C) 0.5 v₁²/2g
(D) 0.375 v₂²/2g

## Q10. The force per unit length is the unit of

(A) Surface tension
(B) Compressibility
(C) Capillarity
(D) Viscosity

## Q11. The coefficient of discharge for an external mouthpiece depends upon

(A) Velocity of liquid
(B) Pressure of liquid
(C) Area of mouthpiece
(D) Length of mouthpiece

## Q12. A flow in which __ force is dominating over the viscosity is called turbulent flow.

(A) Elastic
(B) Surface tension
(C) Viscous
(D) Inertia

## Q13. The tangential velocity of the water element having a free vortex is

(A) Directly proportional to its distance from the centre
(B) Inversely proportional to its distance from the centre
(C) Directly proportional to its (distance)2 from the centre
(D) Inversely proportional to its (distance)2 from the centre

Answer: (B) Inversely proportional to its distance from the centre

(A) Orifice
(B) Notch
(C) Weir
(D) Dam

## Q15. The discharge through a small rectangular orifice is given by (where Cd = Coefficient of discharge for the orifice, a = Cross-sectional area of the orifice, h = Height of the liquid above the centre of the orifice)

(A) Q = Cd × a × 2gh
(B) Q = (2/3). Cd × a × h
(C) Q = (Cd × a)/√(2gh)
(D) Q = (3Cd × a)/√(2h)

Answer: (A) Q = Cd × a × 2gh

## Q16. In order to measure the flow with a Venturimeter, it is installed in

(A) Horizontal line
(B) Inclined line with flow upwards
(C) Inclined line with flow downwards
(D) Any direction and in any location

Answer: (D) Any direction and in any location

(A) Equal to
(B) One-fourth
(C) One-third
(D) One-half

## Q18. Which of the following is an example of laminar flow?

(A) Underground flow
(B) Flow past tiny bodies
(C) Flow of oil in measuring instruments
(D) All of these

## Q19. The discharge over a triangular notch is

(A) Inversely proportional to H3/2
(B) Directly proportional to H3/2
(C) Inversely proportional to H5/2
(D) Directly proportional to H5/2

Answer: (D) Directly proportional to H5/2

## Q20. An open tank containing liquid is moving with an acceleration on an inclined plane. The inclination of the free surface of the liquid will be __ to the acceleration of the tank.

(A) Equal to
(B) Directly proportional
(C) Inversely proportional
(D) None of these