Q 11-09-032JEE MainJEE Main 2026 (4 Apr, Shift 2)Easy
A water spray gun is attached to a hose of cross sectional area $30\ \text{cm}^2$. The gun comprises of $10$ perforations each of cross sectional area of $15\ \text{mm}^2$. If the water flows in the hose with the speed of $50\ \text{cm/s}$, calculate the speed at which the water flows out from each perforation. (Neglect any edge effects)
Answer: (B) $10$ m/s
Continuity: $A_1v_1 = (10 \times a)v_2$.
$30\ \text{cm}^2 \times 50\ \text{cm/s} = 1500\ \text{cm}^3/\text{s}$; total hole area $= 10 \times 15\ \text{mm}^2 = 1.5\ \text{cm}^2$.
$v_2 = \dfrac{1500}{1.5} = 1000$ cm/s $= 10$ m/s.
Solution by Sreeraj P, M.Sc Physics