Question

A liquid is flowing in a cylindrical pipe of internal diameter 4 cm with a velocity if 5 $m{s}^{-1}$. If this tube is joined with another tube of internal diameter 2 cm then the velocity of flow of liquid in the smaller tube will be (in $m{s}^{-1}$)

• A. 10
• B. 40
• C. 5
• D. 20

Answer 1

Answer: (D)

20

We know,

According to equation of continuity,

$Av=constant$

$\frac{\pi D_1^2}{4}\times 5=\frac{\pi D_2^2}{4}\times v$

$v=\frac{5D_1^2}{D_2^2}=5\times 2^2=20m/s$

Option $\text{D}$ is the correct answer