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11.

SI unit of viscosity is

12.

Identify the incorrect statement. Apparent shear forces

A.	Can never occur in frictionless fluid regardless of its motion	B.	Can never occur when the fluid is at rest
C.	Depend upon cohesive forces	D.	Depend upon molecular interchange of momentum
E.	May occur owing to cohesion when the fluid is at rest

13.

The upper critical Reynolds number is

A.	Important from a design view point	B.	The number at which turbulent flow changes to laminar flow
C.	About 2000	D.	Not more than 2000
E.	Of no practical importance in pipe flow problems

14.

The Reynolds number for pipe flow is given by

15.

Alcohol is used in manometers because

A.	It provides a suitable meniscus for the inclined tube	B.	Its density being less can provide longer length for a pressure difference, thus more accuracy can be obtained
C.	(A) and (B) above	D.	Cheap and easily availale
E.	Its vapour pressure is low

16.

The Reyonlds number may be defined as the ratio of

A.	Viscous forces to inertial forces	B.	Elastic forces to pressure forces
C.	Viscous forces to gravity forces	D.	Gravity forces to inertial forces
E.	None of the above

17.

Select the quantity in the following that is not a dimensionless parameter:

A.	Pressure coefficient	B.	Froude number
C.	Darcy weisbach friction factor	D.	Kinematic viscosity
E.	Weber number

18.

The Weber number is the ratio of

A.	Inertial forces to surface tension force	B.	Intertial forces to viscous forces
C.	Elastic forces to pressure forces	D.	Viscous forces to gravity
E.	Elastic forces to gravity

19.

Froude number is useful in calculations for

20.

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

A.	Regardless 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.	Only when fluid is frictionless and incompressible
E.	Only when the fluid has zero viscosity and is at rest