Fluid Mechanics

JEE Main level, single correct, medium

71 of 192

Question 71 of 192


Consider a water jar of radius R that has water filled up to height H and is kept on a stand of height h (see figure). Through a hole of radius r (r<<R)\left(r\lt \lt R\right) at its bottom, the water leaks out and the stream of water coming down towards the ground has a shape like a funnel as shown in the figure. If the radius of the cross-section of water stream when it hits the ground is x. Then:

Show answer and solution

Answer: (A) x=r(HH+h)14x=r{\left(\dfrac{H}{H+h}\right)}^{\dfrac{1}{4}}

Using equation of continuity

πr22gH=πx22g(H+h)\pi {\text{r}}^{2}\sqrt{2\text{gH}}=\pi {\text{x}}^{2}\sqrt{2\text{g}\left(\text{H}+\text{h}\right)}

x=r(HH+h)14\text{x}=\text{r}{\left(\dfrac{\text{H}}{\text{H}+\text{h}}\right)}^{\dfrac{1}{4}}

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.
See it move: Fluid mechanics simulationDrag the sliders and watch the numbers in this question change.

More Physics practice

JEE Main Physics practice question on Fluid Mechanics (Hydrodynamics), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.