Question

If the diameter of a capillary tube is doubled, the rate of flow ofliquid increases

• A. 2 times
• B. 4 times
• C. 8 times
• D. 16 times

Answer 1

Answer: (D)

16 times

Answer 2

Rate of flow of liquid, $Q \propto r^4$.
Now, $d' = 2d$ or $r' = 2r$
$\therefore \:\:\frac{Q'}{Q} = \left( \frac{r'}{r}\right)^{4} = \left(\frac{2r}{r}\right)^{4} = 16$
or $Q' = 16Q$