Top 550+ Solved Fluid Mechanics and Hydraulic Machines MCQ Questions Answer
Q. A small plastic boat loaded with pieces of steel rods is floating in a bath tub. It the cargo is dumped into the water allowing the boat to float empty, the water level in the tub will
a. Fall
b. Fall and then rise
c. Rise and then fall
d. Not change
e. Rise
Q. The velocity in a 2 cm-diameter pipe is 20 m/s. If the pipe enlarges to 5 cm diameter velocity, in m/s, will be
a. 6.4
b. 5.2
c. 3.2
d. 4.8
e. 8
Q. For hydrodynamically rough boundary the friction coefficient
a. Depends on velocity and relative roughness
b. Varies with Reynold's number
c. Depends on Reynolds number, pressure gradient and relative roughness
d. Remains constant
e. Depends on relative roughness
Q. In turbulent flow
a. Cohesion is more effective than momentum transfer in causing shear stress
b. Momentum transfer is on a molecular scale only
c. One lamina of fluid flides smoothly over another
d. Shear stresses are generally larger than in similar laminar flow
e. The fluid particles move in an orderly manner
Q. If a barometer carries wter instead of mercury, the height of column for a pressure equivalent to 75 cm of mercury will be
a. 1034 cm
b. 1040 cm
c. 1000 cm
d. 1050 cm
e. 1020 cm
Q. In which of the following case of modelling, Reynold number will be used for studying?
a. Hydraulic jump
b. Flow configuration of harbours
c. Flow of castor oil through pipes
d. All of the above
Q. A hydro-electric site has a head of 100 m and an average discharge of 10m3/s. Assume 92% efficiency, for a greater speed of 6000 rpm, the specific speed of turbine would be
a. 600
b. 1000
c. 1500
d. 1900
e. None of the above
Q. Bluff body
a. Surface is smooth so that friction can be neglected
b. Surface does not coincide with stream lines
c. Surface perpendicular to stream lines
d. 8.3
e. Surface coincides with stream lines
Q. The horizontal component of force on a curved surface is equal to the
a. Scalar sum of all elemented horizontal components
b. Product of pressure at its centroid and area
c. Weight of liquid retained by the curved surface
d. Weight of liquid vertically above the curved surface
e. Force on a projection of the curved surface into a vertical plane
Q. Froude number is useful in calculations for
a. Hydraulic jump
b. Surface tension force
c. Flow through pipes
d. Compressible flow problems
e. Water hammer
Q. Manning's formula is used to determine
a. Friction head loss in irregular sections
b. Discharge through weirs and notches
c. Friction head loss in open channels
d. Friction hed loss in pipes running full
e. Friction head loss in pipes running partially full
Q. The angle of contact (0) between water and glass tube in case of capillary rise is equal to
a. 90?
b. 128?
c. 10?
d. 157?
e. 0?
Q. In case the velocity vector at different points along a stream line remains unchanged then the flow is termed as
a. Irrotational flow
b. Uniform flow
c. Stoke's flow
d. Rotational flow