Q 11-09-016NEETJEE MainEasy
Water flows through a horizontal pipe whose diameter narrows from $4$ cm to $2$ cm. If the speed in the wide part is $1$ m s$^{-1}$, the speed in the narrow part is
Answer: (C) $4$ m s$^{-1}$
Continuity: $A_1v_1 = A_2v_2$, and $A \propto d^2$.
$v_2 = v_1\left(\dfrac{d_1}{d_2}\right)^2 = 1 \times 4 = 4$ m s$^{-1}$.
Solution by Sreeraj P, M.Sc Physics