Question

An ideal fluid flows through a pipe of circular cross-section made of two section with diameters 2.5 and 3.75 cm . The ratio of the two section is

• A. 9:4
• B. 4:9
• C. 3:2
• D. 2:3

Answer 1

The correct option is A 9:4

$\begin{array}{c}\text{Given,}\\ \text{ideal fluid flowing through pipe of}\\ \text{diameter}\left(d_1\right)=2.5cm\\ \text{and diameter}\left(d_2\right)=3.75cm\\ \frac{v_1}{v_2}=?\end{array}$

$\begin{array}{c}\text{Accoiding to Law Equation of contincity}\\ a_1{v}_1=a_2{v}_2\\ \frac{v_1}{v_2}=\frac{a_2}{a_1}\end{array}$

$\begin{array}{cc}\frac{v_1}{v_2}& =\frac{a_2}{a_1}\\ & =\frac{\left(\frac{\mathrm{x/}{d}_2^2}{4}\right)}{\left(\frac{x{d}_1^2}{4}\right)}\\ & =\frac{d_2^2}{d_1^2}\\ & =\frac{3.75\times 3.75}{2.5\times 2.5}\\ & =\frac{v_1}{v_2}=\frac{9}{4}\end{array}$