Q 11-09-043JEE MainJEE Main 2025 (22 Jan, Shift 2)Easy
A tube of length $L$ is shown in the figure. The radius of cross section at the point (1) is $2\ \text{cm}$ and at the point (2) is $1\ \text{cm}$, respectively. If the velocity of water entering at point (1) is $2\ \text{m/s}$, then velocity of water leaving the point (2) will be
Answer: (D) $8\ \text{m/s}$
Equation of continuity: $A_1v_1 = A_2v_2$, with $A \propto r^2$:
$$v_2 = v_1\left(\frac{r_1}{r_2}\right)^2 = 2\times\left(\frac{2}{1}\right)^2 = 8\ \text{m/s}$$
Solution by Sreeraj P, M.Sc Physics