physical pharmaceutics

The boundary between water and gas is called as

• liquid gas interface

• surface

• interface

• miscible

What is surface tension defined as?

• Density of a liquid

• mass/weight of system

• pressure exterted on surface

• Force acting on the surface of a liquid

Methods used measure surface tension except

• Drop Count Method

• Wilhelmy Plate Method

• Thermal Conductivity Method

• Capillary Rise Method

What is the unit of surface tension in the SI system?

• 
  kg/m²

• N/m

• Pa

• centipoise

role of surfactant

• increases surface tension

• increases surface free energy

• reduces vapor pressure

• reduces surface tension

What is the spreading coefficient (S) when spreading occurs?

• S =-2

• S = 0

• S < 0

• S = 1

Granules in tablets having

• solid solid interface

• solid air surface

• surface

• solid void interface

Surface tension of water in dyne/cm------

• 36

• 86

• 92

• 72

surfactants with HLB 13 is considered as

• Wetting agents

• lipophilic

• Detergents

• anti foaming

Cetyltrimethylammonium bromide is------type of surfactant

• cationic

• anionic

• hydrophilic

• ampholytic