Question

An ideal liquid is flowing through the horizontal tube as shown in figure. If areas of cross-section of end $A$ and $B$ are $2m{m}^2$ and $4m{m}^2$ respectively and velocity of liquid at end $A$ is $4m/s$ then velocity of liquid at end $B$ will be

• A. $4m/s$
• B. $2m/s$
• C. $8m/s$
• D. $1m/s$

Answer 1

The correct option is B $2m/s$

area of $A=2{mm}^2$

area of $B=4{mm}^2$

velocity at $A,V_A=4m/s$

let velocity at $B,V_B$

liquid passed through any cross section

within a Second is constant

$A_1{V}_A=A_2{V}_B$

$2\times 4=4\times V_B$

or $V_B=2m/s$

Correct option is (B).