The velocity of upper layer of water in a river is 36 kmh ⁻¹. Shearing stress between horizontal layers of water is 10 - 3 Nm ⁻². Depth of the river is __________ m. (Co-efficient of viscosity of water is 10 - 2 Pa.s) Numerical answer type. Work it out, then open the answer.

Answer: 100. v = 36 km/h = 10 m/s; stress = /h (bottom layer at rest). h = (η v)/(stress) = 10⁻²×1010⁻³ h = 100 m

The velocity of upper layer of water in a river is 36 kmh ⁻¹… | JEE Main 2022 (25 Jun, Shift 1)

Q19JEE Main 2022 · 25 JUN · SHIFT 1Medium

Viscosity & Stokes' Law

The velocity of upper layer of water in a river is 36 kmh ${}^{-1}$ . Shearing stress between horizontal layers of water is 10 $-$ 3 Nm ${}^{-2}$ . Depth of the river is __________ m. (Co-efficient of viscosity of water is 10 $-$ 2 Pa.s)

Numerical answer type. Work it out, then open the answer.

Show answer and solution

Answer: 100

$v = 36\text{ km/h} = 10$ m/s; stress $= \eta\frac{v}{h}$ (bottom layer at rest).
$h = \frac{\eta v}{\text{stress}} = \frac{10^{-2}\times10}{10^{-3}}$
$h = 100$ m

Report a mistake

Viscosity & Stokes' Law question from JEE Main 2022 (25 Jun, Shift 1)

More questions on Viscosity & Stokes' Law