JEE Main 2022PhysicsMechanical Properties of FluidsMediumNumerical

JEE Main 2022 — Mechanical Properties of Fluids Question with Solution

JEE Main 2022 (25 Jun Shift 1)

Question

The velocity of upper layer of water in a river is 36 km h-1. Shearing stress between horizontal layers of water is 10-3 N m-2. Depth of the river is _____ m. (Co-efficient of viscosity of water is 10-2 Pa s)

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Show full solutionCorrect answer: 100
Correct answer
100

Step-by-step explanation

The viscous force formula is given by,

F=-ηAdvdy

Therefore, shear stress FA=-ηdvdy. Here negative sign tells us that the direction of force is opposite to the velocity gradient.

⇒FA=ηdvdy

Now v=36×518=10 m s-1 and if the depth is d

dvdy=10d

⇒10-3=10-2×10d⇒d=100 m

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About this question

This is a previous-year question from JEE Main 2022, covering the Mechanical Properties of Fluids chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.