Which of the following is false about viscosity? a. The ...

[michelleunicorn]

Which of the following is false about viscosity?
 
  a. The greater the viscosity, the greater is the opposition to flow.
  b. Viscosity is most important under condi-tions of turbulent flow.
  c. The stronger the cohesive forces, the greater the viscosity.
  d. Fluid viscosity is equivalent to friction between solids.

Question 2

After placing a liquid into a small-diameter glass tube, you observe the formation of a convex (upwardly curved) meniscus. What conclusion is correct?
 
  a. The liquid must have a very low surface tension.
  b. Strong adhesive forces exist between the liquid and glass.
  c. The liquid must have an extremely high viscosity.
  d. Strong cohesive forces exist among the liquid molecules.

[leahchrapun]

Answer to Question 1

ANS: B
Laminar flow consists of concentric layers of fluid flowing parallel to the tube wall at velocities that increase toward the center.

Answer to Question 2

ANS: D
When the liquid is water, the meniscus is concave because the water molecules at the surface ad-here to the glass more strongly than they cohere to each other. In contrast, a mercury meniscus is convex. In this case, the cohesive forces pulling together the mercury atoms exceed the adhesive forces trying to attract the mercury to the glass.