Which unit is used to quantify viscosity in the material?

• A. Poise
• B. Pascal
• C. Newton
• D. Joule

Answer: (B)

Viscosity is a measure of how much a fluid resists flowing, i.e., how thick or sticky it is. The unit traditionally used to quantify this property in the CGS system is the poise, which reflects the shear stress required to produce a given rate of deformation between layers. In the SI system, viscosity is expressed as dynamic viscosity in Pascal-seconds, since it combines pressure and time. The other options correspond to different physical quantities: pascal is a unit of pressure, newton is a unit of force, and joule is a unit of energy. Remember that 1 Poise equals 0.1 Pascal-seconds, linking the two systems. Therefore, the unit used to quantify viscosity is Poise (or Pascal-seconds in SI).