Unit of dynamic viscosity in the CGS system In the centimetre–gram–second (CGS) system, what is the unit of dynamic viscosity?

Introduction / Context:
Viscosity units vary with unit systems. Converting and recognizing units correctly is essential when reading material property tables or correlating experimental data across metric and CGS literature.

Given Data / Assumptions:

• Dynamic viscosity μ is being asked (not kinematic viscosity ν).
• CGS (centimetre–gram–second) unit system.

Concept / Approach:

In CGS, the unit of dynamic viscosity is the poise (P). One poise equals 1 g/(cm·s), and 1 P = 0.1 Pa·s in SI. Kinematic viscosity in CGS uses stokes (St), where 1 St = 1 cm^2/s.

Step-by-Step Solution:

Verification / Alternative check:

Typical dynamic viscosity of water at 20°C is about 1 cP (centipoise) = 0.001 Pa·s, matching the conversion above.

Why Other Options Are Wrong:

Dyne and Newton are force units; joule is energy; “none” is unnecessary because poise is the standard CGS unit.

Common Pitfalls:

Confusing centipoise (cP) with poise (P); many data sheets list viscosity in cP, where 1 cP = 0.01 P.

Final Answer:

Poise