fluid mechanics mechanical engineering Mcqs
101. Dimensions of surface tension are___________________?
comments icon0

A. MlL r2

B. MlL2T2

C. MlLTx

D. MlLT2

E. MlLt

102. A square surface 3 m x 3 m lies in a vertical line in water pipe its upper edge at water surface. The hydrostatic force on square surface is____________________?
comments icon0

A. 30,000 kg

B. 9,000 kg

C. 27,000 kg

D. 13,500 kg

E. 18,000 kg

103. The total pressure force on a plane area is equal to the area multiplied by the intensity of pressure at the centriod, if___________________?
comments icon0

A. the area is vertical

B. all of the above

C. none of the above

D. the area is inclined

E. the area is horizontal

104. Piezometer is used to measure_____________________?
comments icon0

A. difference of pressure between two points

B. very low pressures

C. atmospheric pressure

D. flow

E. pressure in pipe, channels etc.

105. Total pressure on a lmxlm gate immersed vertically at a depth of 2 m below the free water surface will be_______________?
comments icon0

A. 2000 kg

B. 1000 kg

C. 4000 kg

D. 8000 kg

E. 16000 kg

106. A balloon lifting in air follows the following principle_____________________?
comments icon0

A. law of gravitation

B. Archimedes principle

C. all of the above

D. principle of buoyancy

E. continuity equation

107. Cavitation is caused by_____________________?
comments icon0

A. weak material

B. high pressure

C. low viscosity

D. high velocity

E. low pressure
108. Two pipe systems can be said to be equivalent, when the following quantities are same__________________?
comments icon0

A. flow and length

B. friction loss and flow

C. friction factor and diameter

D. length and diameter

E. velocity and diameter

109. An odd shaped body weighing 7.5 kg and occupying 0.01 m3 volume will be completely submerged in a fluid having specific gravity of__________________?
comments icon0

A. 1.2

B. 1

C. 0.75

D. 1.25

E. 0.8

110. The process of diffusion of one liquid into the other through a semi-permeable membrane is called_______________________?
comments icon0

A. diffusivity

B. surface tension

C. cohesion

D. viscosity

E. osmosis
111. The time oscillation of a floating body with increase in metacentric height will be_________________?
comments icon0

A. same

B. higher

C. lower/higher depending on weight of body

D. lower

E. unpredictable

112. The flow which neglects changes in a transverse direction is known as_________________?
comments icon0

A. turbulent flow

B. uniform flow

C. one dimensional flow

D. streamline flow

E. steady flow

113. In a forced vortex, the velocity of flow everywhere within the fluid is__________________?
comments icon0

A. unpredictable

B. non-zero finite

C. minimum

D. maximum

E. zero

114. The normal stress is same in all directions at a point in a fluid_______________?
comments icon0

A. irrespective of the motion of one fluid layer relative to an adjacent layer

B. when there is no motion of one fluid layer relative to an adjacent layer

C. only when the fluid is frictionless

D. in case of an ideal fluid

E. only when the fluid is incompressible and has zero viscosity

115. Property of a fluid by which molecules of different kinds of fluids are attracted to each other is called________________?
comments icon0

A. viscosity

B. adhesion

C. cohesion

D. compressibility

E. surface tension

116. A liquid compressed in cylinder has a volume of 0.04 m3 at 50 kg/cm2 and a volume of 0.039 m3 at 150 kg/cm2. The bulk modulus of elasticity of liquid is___________________?
comments icon0

A. 40 x 106 kg/cm2

B. none of the above

C. 40 x 105 kg/cm2

D. 400 kg/cm2

E. 4000 kg/cm2
117. Eulers dimensionless number relates the following__________________?
comments icon0

A. viscous force and buoyancy force

B. inertial force and gravity

C. pressure force and viscous force

D. viscous force and inertial force

E. pressure force and inertial force
118. For similarity, in addition to models being geometrically similar to prototype, the following in both cases should also be equal____________________?
comments icon0
A. all the four ratios of inertial force to force due to viscosity, gravitation, sur-face tension, and elasticity

B. ratio of inertial force to force due to surface tension

C. ratio of inertial force to force due to viscosity

D. ratio of inertial force to force due to gravitation

119. A large Roynold number is indication of________________?
comments icon0

A. steady flow

B. highly turbulent flow

C. smooth and streamline flow

D. laminar flow

E. turbulent flow

120. A model of a reservior is drained in 4 mts by opening the sluice gate. The model scale is 1: 225. How long should it take to empty the prototype ?
comments icon0

A. 4 minutes

B. 4 x (225)3/2 minutes

C. 4 (225)1/3 minutes

D. 900 minutes

E. 4 x V225 minutes
121. When a body floating in a liquid, is displaced slightly, it oscillates about _________________?
comments icon0

A. center of buoyancy

B. center of pressure

C. liquid surface

D. e.g. of body

E. metacentre
122. A bucket of water is hanging from a spring balance. An iron piece is suspended into water without touching sides of bucket from another support. The spring balance reading will_________________?
comments icon0

A. increase/decrease depending on depth of immersion

B. remain same

C. decrease

D. unpredictable

E. increase

123. Mercury is often used in barometer because____________________?
comments icon0

A. it is the best liquid

B. the height of barometer will be less

C. its vapour pressure is so low that it may be neglected

D. both B. and C.

E. it moves easily

124. A fluid in equilibrium cant sustain____________________?
comments icon0

A. tensile stress

B. bending stress

C. shear stress

D. compressive stress

E. all of the above

125. If the atmospheric pressure on the surface of an oil tank (sp. gr. 0.8) is 0.2 kg/cm, the pressure at a depth of 50 m below the oil surface will be_________________?
comments icon0

A. 3 meters of water column

B. 2 meters of water column

C. 6 meters of water Column

D. 7 meters of water column

E. 5 meters of water column

126. For a floating body to be in equilibrium_____________________?
comments icon0

A. meta centre should be above e.g.

B. none of the above

C. centre of buoyancy and e.g. must lie on same vertical plane

D. all of the above

E. a righting couple should be formed

127. A perfect gas____________________?
comments icon0

A. has constant viscosity

B. has zero viscosity

C. is in compressible

D. is of theoretical interest

E. none of the above
128. Which of the following instrument can be used for measuring speed of a submarine moving in deep sea__________________?
comments icon0

A. Orifice plate

B. pitot tube

C. hot wire anemometer

D. rotameter

E. Venturimeter

129. For a floating body to be in stable equilibrium, its metacentre should be___________________?
comments icon0

A. below the center of buoyancy

B. between e.g. and center of pressure

C. below the center of gravity

D. above the center of buoyancy

E. above the center of gravity
130. The capillary rise at 20C in a clean glass tube of 1 mm bore containing water is approximately____________________?
comments icon0

A. 5 mm

B. 1 mm

C. 20 mm

D. 10 mm

E. 30 mm
131. Capillary action is due to the_________________?
comments icon0

A. surface tension

B. cohesion of the liquid

C. adhesion of the liquid molecules and the molecules on the surface of a solid

D. none of the above

E. all of the above
132. A liquid would wet the solid, if adhesion forces as compared to cohesion forces are________________?
comments icon0

A. less at low temperature and more at high temperature

B. there is no such criterion

C. more

D. equal

E. less

133. The units of dynamic or absolute viscosity are__________________?
comments icon0

A. none of the above

B. metres2 per sec

C. newton-sec per meter

D. newton-sec2 per meter

E. kg sec/meter

134. The speed of sound in a ideal gas varies directly as its__________________?
comments icon0

A. modulus of elasticity

B. density

C. absolute temperature

D. temperature

E. pressure

135. Operation of McLeod gauge used for low pressure measurement is based on the principle of_________________?
comments icon0

A. Pascals law

B. Boyles law

C. Charles law

D. McLeods law

E. gas law

136. Mach number is significant in_____________________?
comments icon0

A. simultaneous motion through two fluids where there is a surface of dis-continuity, gravity force, and wave making effects, as with ships hulls

B. full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.

C. all of fhe above

D. none of the above

E. supersonics, as with projectiles and jet propulsion
137. An ideal flow of any fluid must satisfy __________________?
comments icon0

A. Pascal law

B. Bernoullis theorem

C. boundary layer theory

D. Newtons law of viscosity

E. continuity equation
138. Center of pressure on an inclined plane is___________________?
comments icon0

A. at metacentre

B. at center of pressure

C. above the centroid

D. below the centroid

E. at the centroid

139. To avoid an interruption in the flow of a syphon, an air vessel is provided__________________?
comments icon0

A. none of the above

B. ay nay point between inlet and outlet

C. at the inlet

D. at the summit

E. at the outlet

140. Liquids_________________?
comments icon0

A. are not viscous

B. occupy definite volume

C. cannot be compressed

D. are not affected by change in pressure and temperature

E. none of the above
141. Barometer is used to measure__________________?
comments icon0

A. very low pressure

B. rain level

C. difference of pressure between two points

D. atmospheric pressure

E. pressure in pipes, channels etc.

142. The center of pressure of a surface subjected to fluid pressure is the point_______________?
comments icon0

A. similar to metacentre

B. where pressure equivalent to hydraulic thrust will act

C. on the surface at which gravitational force acis

D. on the surface at which resultant pres-sure acts

E. at which all hydraulic forces meet

143. Flow of water in a pipe about 3 metres in diameter can be measured by__________________?
comments icon0

A. orifice plate

B. nozzle

C. venturi

D. rotameter

E. pitot tube
144. The conditions for the stable equilibrium of a floating body are___________________?
comments icon0
A. all the above are correct

B. a righting couple should be formed

C. the center of buoyancy and the center of gravity must lie on the same vertical line

D. none of the above is correct

E. the meta-center should lie above the center of gravity

145. A one dimensional flow is one which_________________?
comments icon0
A. involves zero transverse component of flow

B. is steady uniform flow

C. takes place in one dimension

D. takes place in straight lines

E. is uniform flow

146. If mercury in a barometer is replaced by water, the height of 3.75 cm of mercury will be following cm of water________________?
comments icon0

A. 52.2 cm

B. 51 cm

C. 50 cm

D. 52 cm

E. 51.7 cm

147. The upper surface of a weir over which water flows is known is_____________________?
comments icon0

A. contracta

B. sill

C. nappe

D. crest

E. weir top

148. In a free vortex motion, the radial component of velocity everywhere is________________?
comments icon0

A. non-zero and finite

B. unpredictable

C. zero

D. maximum

E. minimum

149. Free surface of a liquid behaves like a sheet and tends to contract to smallest possible area due to the_________________?
comments icon0

A. none of die above

B. force of friction

C. force of cohesion

D. force of diffusion

E. force of adhesion

150. The bulk modulus of elasticity___________________?
comments icon0

A. has the dimensions of 1/pressure

B. increases with pressure

C. is large when fluid is more compressible

D. is independent of pressure and viscosity

E. is directly proportional to flow