71. Flow in pipes is turbulent if Reynold number is

A. less than 2100

B. more than 3000

C. between 2100 and 3000

D. none of these.

72. Equation of continuity of flow is based on the principle of conservation of

A. mass

B. momentum

C. force

D. none of these.

73. The velocity of the fluid particle at the centre of the pipe section, is

A. minimum

B. maximum

C. equal throughout

D. none of these.

74. For solving the problems is hydraulic engineering, the velocity used is

A. velocity at the centre of pipe section

B. average velocity of flow over a section

C. mean of the velocities at the centre and that along the pipe surface

D. none of these.

75. The flow is called rotational if its velocity normal to the plane of area is equal to

A. angular velocity vector

B. twice the angular velocity vector

C. thrice the angular velocity vector

D. none of these.

76. For an irrotational flow, the equation y*v= 0 is given by

A. Cauchy-Riemann

B. Reynold

C. Laplaces

D. Bernoulli.

77. 'Flow net' can be drawn only if the flow is

A. turbulent

B. rotational

C. distortion

D. none of these.

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