Question

If the kinematic viscosity of a liquid is 6 stokes and specific gravity is 1.9, then what would be its dynamic viscosity?

• A. 10 poise
• B. 11.4 poise
• C. 8.6 poise
• D. 7.9 poise

Hint:

Direct calculation: $\mu (\text{poise}) = \nu (\text{stokes}) \times \text{Specific Gravity} = 6 \times 1.9 = 11.4\text{ poise}$.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Kinematic viscosity is the ratio of dynamic viscosity to fluid mass density, with conversions standardly executed in CGS units (stokes and poise).
Key Formula or Approach:
\[ \nu = \frac{\mu}{\rho} \implies \mu = \nu \times \rho \]
where \(\nu\) is in stokes (\(\text{cm}^2\text{/s}\)), \(\rho\) is in \(\text{g/cm}^3\), and \(\mu\) is in poise (\(\text{dyne}\cdot\text{s/cm}^2\) or \(\text{g/cm}\cdot\text{s}\)).

Step 2: Detailed Explanation:
Given parameters in CGS units:
- Kinematic viscosity: \(\nu = 6\text{ stokes} = 6\text{ cm}^2\text{/s}\)
- Specific gravity: \(\text{SG} = 1.9 \implies \rho = 1.9\text{ g/cm}^3\)
Computing dynamic viscosity:
\[ \mu = \nu \times \rho = 6\text{ cm}^2\text{/s} \times 1.9\text{ g/cm}^3 = 11.4\text{ poise} \]

Step 3: Final Answer:
Hence, the dynamic viscosity is 11.4 poise, matching option (B).