# Hydraulics and Fluid Mechanics – Section 1

11. The length AB of a pipe ABC in which the liquid is flowing has diameter (d1) and is suddenly enlarged to diameter (d2) at B which is constant for the length BC. The loss of head due to sudden enlargement is 12. The coefficient of contraction is the ratio of

A. actual velocity of the jet at vena contracta to the theoretical velocity
B. loss of head in the orifice to the head of water available at the exit of the orifice
C. actual discharge through an orifice to the theoretical discharge
D. area of the jet at vena contracta to the area of orifice

Correct Answer: D. area of the jet at vena contracta to the area of orifice

13. In a free nappe,

A. the pressure below the nappe is atmospheric
B. the pressure below the nappe is negative
C. the pressure above the nappe is atmospheric
D. the pressure above the nappe is negative

Correct Answer: A. the pressure below the nappe is atmospheric

14. The Reynold’s number of a ship is __________ to its velocity and length.

A. directly proportional
B. inversely proportional

15. When a tube of smaller diameter is dipped in water, the water rises in the tube due to the viscosity of water.

A. True
B. False

16. According to equation of continuity,

A. w1a1 = w2a2
B. w1v1 = w2v2
C. a1v1 = a2v2
D. a1/v1 = a2/v2

Correct Answer: C. a1v1 = a2v2

17. The coefficient of resistance is the ratio of

A. actual velocity of the jet at vena contracta to the theoretical velocity
B. area of jet at vena contracta to the area of orifice
C. loss of head in the orifice to the head of water available at the exit of the orifice
D. actual discharge through an orifice to the dieoretical discharge

Correct Answer: C. loss of head in the orifice to the head of water available at the exit of the orifice

18. Euler’s equation in the differential form for the motion of liquids is given by 19. 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

Correct Answer: D. any direction and in any location

20. The discharge through a large rectangular orifice is given by (where H1 = Height of the liquid above the top of the orifice, H2 = Height of the liquid above the bottom of the orifice, b = Breadth of the orifice, and Cd = Coefficient of discharge) 