Momentum Transfer

Question 1

The fluid property, due to which, mercury does not wet the glass is
a. surface tension
b. viscosity
c. cohesion
d. adhesion

Answer 1

Surface Tension

Question 2

What is the SI unit of surface tension?

Answer 2

N/m

Question 3

The viscosity of a gas

Answer 3

increases with increase in temperature

Question 4

The dimensionless numver that characterizes fluid flows in a conduit is

Answer 4

Reynolds number

Question 5

Natural convection

Answer 5

Grashof Number

Question 6

Mass Transfer

Answer 6

Peclet number

Question 7

Nu= hD/k in convective heat transfer is

Answer 7

Nusselt Number

Question 8

Turbulent flow generally occurs for cases involving
a. viscous fluid
b. very narrow capillary tubes
c. very slow motions
d. none of these

Answer 8

None of these

Question 9

The normal stress is the same in all directions at a point in a fluid when the fluid is

Answer 9

having no motion of one fluisnlayer relarive to the layer

Question 10

Which of the following statements is TRUE about Newton’s law of viscosity

Answer 10

it applies only to Newtonian fluid

Question 11

At high Reynolds numbers

Answer 11

inertial forces control and viscous forces are not significant

Question 12

The dimension of dynamic viscosity is (t notation here is time)

Answer 12

ML^-1t^-1

Question 13

The ratio of average fluid velocity to the maximum velocity in casebof laminar flow of a Newtonian fluid in a circular pipe is

Answer 13

0.5

Question 14

The ratio od average fluid velocity to the maximum velocity in case of turbulent flow of a Newtonian fluid in a circular pipe is

Answer 14

1

Question 15

If teo similar horizontal pipes are to be connceted, which od the following fittings should be used?

Answer 15

Union

Question 16

If a pump delivers water to a destination tank at high elevation, which od the following valves will protect the pump from unintended fluid backflow?

Answer 16

Check valve

Question 17

Which of the following phenomena describes the formation of bubbles in liquid flow when the local pressure falls to around the vapor pressure of the fluid?

Answer 17

Cavitation

Question 18

If a piping system delivers corrosive and abrasive fluids, which od the following should ne used to control the flow?

Answer 18

Diaphragm valve

Question 19

Which valve id used accurately to regulate the flow of liquids and gases at low flow rates?

Answer 19

Needle valve

Question 20

When a fluid flows through a reducer in a piping system, the velocity at the outlet ens is ___ the velocity at the inlet

Answer 20

greater than

Question 21

Which of the following statements is FALSE?
a. Potential flow is a flow of compressible fluids with no shear
b. Rotameters are variable head meters
c. There are 8 schedule numbers in use for standard pipes
d. Roughness has no appreciable effect on the friction factor when the flow is laminar

Answer 21

c. There are 8 schedule numbers in use for standard pipes

Question 22

Which of the folloeinf statements is FALSE?
a. A pump will operate safely if its NPSHA is greater than NPSHR
b. Fans and blowers are used to transport gases
c. Pumps and blowers increase the mechanical energy of the fluid
d. The power loss due to friction in a venturi meter is greater than an orifice meter

Answer 22

d. The power loss due to friction in a venturi meter is greater than an orifice meter

Question 23

For transport of air with pressure drops lessbtgan 0.03 bar, which od the following is used?

Answer 23

Fan (negligible pressure drop isipin mo ang electric fan, compressors have high pressure drops)

Question 24

What do you call the input power delivered by the motor to the pump?

Answer 24

Brake horsepower

Question 25

Which of the following meters will havr the highest permanent pressure loss?

Answer 25

Orifice meter