# Hydraulics and Fluid Mechanics MCQ – Set 02

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(A) 25 kN/ m²
(B) 245 kN/ m²
(C) 2500 kN/m²
(D) 2.5 kN/ m²

## Q2. When a body is immersed wholly or partially in a liquid, it is lifted up by a force equal to the weight of liquid displaced by the body. This statement is called

(A) Pascal’s law
(B) Archimedes’s principle
(C) Principle of flotation
(D) Bernoulli’s theorem

## Q3. The vapour pressure over the concave surface is

(A) Less man the vapour pressure over the plane surface
(B) Equal to the vapour pressure over the plane surface
(C) Greater than the vapour pressure over the plane surface
(D) Zero

Answer: (A) Less man the vapour pressure over the plane surface

## Q4. Principle of similitude forms the basis of

(A) Comparing two identical equipments
(B) Designing models so that the result can be converted to prototypes
(C) Comparing similarity between design and actual equipment
(D) Hydraulic designs

Answer: (B) Designing models so that the result can be converted to prototypes

## Q5. Which of the following statement is correct?

(A) In a compressible flow, the volume of the flowing liquid changes during the flow
(B) A flow, in which the volume of the flowing liquid does not change, is called incompressible flow
(C) When the particles rotate about their own axes while flowing, the flow is said to be rotational flow
(D) All of the above

Answer: (D) All of the above

## Q6. The continuity equation is connected with

(A) Open channel/pipe flow
(B) Compressibility of fluids
(C) Conservation of mass

## Q7. The discharge in an open channel corresponding to critical depth is

(A) Zero
(B) Minimum
(C) Maximum
(D) None of these

## Q8. The center of gravity of the volume of the liquid displaced by an immersed body is called

(A) Metacentre
(B) Center of pressure
(C) Center of buoyancy
(D) Center of gravity

(A) 0.34 times
(B) 0.67 times
(C) 0.81 times
(D) 0.95 times

## Q10. When the Venturimeter is inclined, then for a given flow it will show __ reading.

(A) Same
(B) More
(C) Less
(D) None of these

## Q11. Which of the following instruments is used to measure flow on the application of Bernoulli’s theorem?

(A) Venturimeter
(B) Orifice plate
(C) Nozzle
(D) All of the above

Answer: (D) All of the above

## Q12. The Metacentric heights of two floating bodies A and B are 1 m and 1.5 m respectively. Select the correct statement.

(A) The bodies A and B have equal stability
(B) The body A is more stable than body B
(C) The body B is more stable than body A
(D) The bodies A and B are unstable

Answer: (C) The body B is more stable than body A

## Q13. The units of kinematic viscosity are

(A) Metres² per sec
(B) kg sec/metre
(C) Newton-sec per metre
(D) Newton-sec per metre

## Q14. The velocity of the liquid flowing through the divergent portion of a Venturimeter

(A) Remains constant
(B) Increases
(C) Decreases
(D) Depends upon mass of liquid

## Q15. A weir is said to be narrow-crested weir, if the width of the crest of the weir is __ half the height of water above the weir crest.

(A) Equal to
(B) Less than
(C) More than
(D) None of these

## Q16. The error in discharge (dQ/Q) to the error in measurement of head (dH/H) over a triangular notch is given by

(A) dQ/Q = 3/2 × (dH/H)
(B) dQ/Q = 2 × (dH/H)
(C) dQ/Q = 5/2 × (dH/H)
(D) dQ/Q = 3 × (dH/H)

Answer: (C) dQ/Q = 5/2 × (dH/H)

(A) 10 m/sec²
(B) 9.81 m/sec²
(C) 9.75 m/sec²
(D) 9 m/sec

## Q18. The hammer blow in pipes occurs when

(A) There is excessive leakage in the pipe
(B) The pipe bursts under high pressure of fluid
(C) The flow of fluid through the pipe is suddenly brought to rest by closing of the valve
(D) The flow of fluid through the pipe is gradually brought to rest by closing of the valve

Answer: (C) The flow of fluid through the pipe is suddenly brought to rest by closing of the valve

## Q19. Non uniform 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) Velocity, depth, pressure, etc. change from point to point in the fluid flow
(D) The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane

Answer: (C) Velocity, depth, pressure, etc. change from point to point in the fluid flow

## Q20. The velocity at which the flow changes from laminar flow to turbulent flow is called

(A) Critical velocity
(B) Velocity of approach
(C) Sub-sonic velocity
(D) Super-sonic velocity