Question

The total area of cross section is 0.25 m${}^2$. If blood is flowing at the rate of 100 $c{m}^3{s}^{-1}$, then the average velocity of flow of blood through the capillary, in $mm{s}^{-1}$ is:

• A. 0.4
• B. 4
• C. 25
• D. 400

Answer 1

The correct option is A 0.4

Flow rate of blood $=100c{m}^3/s$$=100\times {10}^{3}m{m}^3/s$
Total area of cross section $=0.25m^2$$=0.25\times {10}^{6}m{m}^2$
So, average velocity of blood through cappileries $=\frac{{10}^5}{{10}^6\times 0.25}mm/s$$=0.4mm/s$