Font size
WorksheetsBioMEMS 2
Total questions: 10
Worksheet time: 5mins
(a) Calculate the Reynolds number, NR, for glycerin at 25oC with the diameter of the pipe is 150 mm, moving with the velocity at 3.8 m/s, and the density, ρ, is 1258 kg/m3 and the dynamic viscosity, η, is 0.96 kg/ms.
(a)
What is the behavior of Re (NR) of a fluid flow below a threshold value?
(a)
Which of these statements are true?
An interface is a smooth surface separating two materials.
The balance of relative forces at an interface leads to surface tension
The interfaces are ideally smooth and the molecules from these materials show good separation at the interface.
In reality, the interfaces are not smooth, molecules from these materials mingle at an interface.
Which of this tells us about the Van der Waals forces?
It arises from electrostatic interaction of ions or of ionic groups.
It is an electrostatic attraction between polar groups of the molecule.
The attraction and repulsion forces which arises between atoms and molecules.
The forces resulted from covalent bonding in molecules.
E is usually presents the:
The total surface area of an interface.
Total energy stored in the interface.
Effective surface area of a molecule
The characteristic dimension of a molecule.
What is the unit for surface tension?
(a)
What are the effects can contribute to capillary action?
Minimization of surface energy.
Pressure difference due to curvature of interface.
Specific force of the movement of liquid through thin tubes.
Maximization of surface energy.
If the liquid is water, solids with a contact angle more than 90o are:
(a)
Which of these describe capillary rise?
It is a balance of surface energy and gravitational potential energy.
Best describe by Jurin's Law.
For a contact angle less than 90o, the liquid will rise in the tube.
For a contact angle less than 90o, the liquid will fall in the tube
The maximum height of a liquid in a capillary tube is inversely proportional to the tube's diameter. (True or False?)
(a)
