Question

The rate at which water flows through a capillary of length $0.5m$ with an internal diameter of $1mm,$ coefficient of viscosity $1.3\times {10}^{-3}kg{m}^{-1}{s}^{-1}$ and pressure head $20cm$ of water in cc. per second is:

• A. $7.4\times {10}^{-2}$
• B. $3.7\times {10}^{-2}$
• C. $74\times {10}^{-2}$
• D. $7.4$

Answer 1

The correct option is A $7.4\times {10}^{-2}$

Applying poiseuillis equation,

$Q=\frac{\Delta P\pi r^4}{8\eta l}$
$Q=\frac{1\times 980\times 20\times \pi \times {\left(0.05\right)}^4}{8\times 1.3\times {10}^{-2}\times 50}$
$\Rightarrow Q=7.4\times {10}^{-2}c{m}^3/s$