##### Q71. Reynold’s number is defined as the

(a) ratio of inertia force to gravity force
(b) ratio of viscous force to gravity force
(c) ratio of viscous force to elastic force
(d) ratio of inertia force to viscous force.

Ans:  (d) ratio of inertia force to viscous force.

##### Q72. Froude’s number is defined as the ratio of

(a) inertia force to viscous force
(b) inertia force to gravity force
(c) inertia force to elastic force
(d) inertia force to pressure force.

Ans: (b) inertia force to gravity force

##### Q73 Mach number is defined as the ratio of

(a) inertia force to viscous force
(b) viscous force to surface tension force
(c) viscous force to elastic force
(d) inertia force to elastic force.

Ans:  (d) inertia force to elastic force.

##### Q74. The pressure rise (pi) due to water hammer depends on

(a) the diameter of pipe only
(b) the length of pipe only
(c) the required to close the valve only
( d ) all of the above.

Ans:  ( d ) all of the above.

##### Q75. Water-hammer in pipes takes place when

(a) fluid is flowing with high velocity
(b) fluid is flowing with high pressure
(c) flowing fluid is suddenly brought to rest by closing the valve
(d) flowing fluid is gradually brought to rest.

Ans:  (c) flowing fluid is suddenly brought to rest by closing the valve

(a) 50%
(b) 66.67%
(c) 75%
(d) 100%.

Ans:  (b) 66.67%

##### Q77.The velocity distribution in turbulent flow for pipes is given by

(a) u = Umax+ 5.5 u* loge (y/R)

(b) u = 2.5 u* loge(y/R)

(c) u = Umax+ 2.5 u*loge (y/R)

(d) none of the above.
where u* = Shear velocity, R = Radius of pipe, y = Distance from pipe wall, U= Centre*Umax line velocity.

Ans:  (c) u = Umax+ 2.5 u*loge (y/R)

##### Q78.When the pipes are connected in parallel, the total loss of head

(a) is equal to the sum of the loss of head in each pipe
(b) is same as in each pipe
(c) is equal to the reciprocal of the sum of loss of head in each pipe
(d) none of the above.

Ans:  (b) is same as in each pipe

##### Q79.When the pipes are connected in series, the total rate of flow

(a) is equal to the sum of the rate of flow in each pipe
(b) is equal to the reciprocal of the sum of rate of flow in each pipe
(c) is the same as flowing through each pipe
(d) none of the above.

Ans:  (c) is the same as flowing through each pipe

##### Q80. Power transmitted through pipes will be maximum when

(a) head lost due to friction = 1/2 total head at inlet of the pipe
(b) head lost due to friction = 1/4 total head at inlet of the pipe
(c) head lost due to friction = total head at the inlet of the pipe
(d) head lost due to friction = 1/3 total head at the inlet of the pipe.

Ans:  (d) head lost due to friction = 1/3 total head at the inlet of the pipe.

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##### Read More Sections of Automobile Engineering

Each section contains maximum 80 Questions. To practice more questions visit other sections.

Hydraulics and Fluid mechanics MCQ-Section-1

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Hydraulics and Fluid mechanics MCQ-Section-3

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Hydraulics and Fluid mechanics MCQ-Section-5