Question

An ideal fluid flown through a pipe of circular cross-section made of two sections with diameters 25 an and 3.75 cm. The ratio of the velocities in the two pipes is

• A. 9 : 4
• B. 3 : 2
• C. $\sqrt{3}:\sqrt{2}$
• D. $\sqrt{2}:\sqrt{3}$

Answer 1

The correct option is A 9 : 4

According to equation of continuity
$a_1{v}_1=a_2{v}_2$

or $\frac{v_1}{v_2}=\frac{a_1}{a_2}$

$=\frac{\pi d_2^2/4}{\pi d_1^2/4}$$={\left(\frac{d_2}{d_1}\right)}^2$

$={\left(\frac{3.75}{2.50}\right)}^2=\frac{9}{4}$