The viscous drag acting on a metal sphere of diameter 1 mm, falling through a fluid of viscosity 0.8 Pa s with a velocity of 2 m s⁻¹ is equal to: (a) 15 × 10⁻³ N (b) 30 × 10⁻³ N (c) 1.5 × 10⁻³ N (d) 20 × 10⁻³ N

Answer: (a). Stokes' law: F = 6πη r v, with r = 0.5 mm = 5×10⁻⁴ m. F = 6π(0.8)(5×10⁻⁴)(2) = 4.8π×10⁻³ F ≈ 15×10⁻³ N So the answer is (a) 15×10⁻³ N.

The viscous drag acting on a metal sphere of diameter 1 mm, falling… | NEET 2023

Q13NEET 2023Easy

Viscosity & Stokes' Law

The viscous drag acting on a metal sphere of diameter $1\text{ mm}$ , falling through a fluid of viscosity $0.8\text{ Pa}$ s with a velocity of $2\text{ m s}^{-1}$ is equal to:

Show answer and solution

Answer: (a)

Stokes' law: $F = 6\pi\eta r v$ , with $r = 0.5\text{ mm} = 5\times10^{-4}$ m.
$F = 6\pi(0.8)(5\times10^{-4})(2) = 4.8\pi\times10^{-3}$
$F \approx 15\times10^{-3}$ N
So the answer is (a) $15\times10^{-3}$ N.

Report a mistake

More questions on Viscosity & Stokes' Law

A metal sphere of mass ' m ' and density ' σ₁ ' falls with terminal velocity through a…MHT CET 2023 (10 May, Shift 2)
A small ball of mass M and density ρ is dropped in a viscous liquid of density ρ₀. After…JEE Main 2023 (6 Apr, Shift 1)
A metal block of base area 0.20 m ² is placed on a table, as shown in figure. A liquid…JEE Main 2023 (29 Jan, Shift 2)
A Spherical ball of radius 1mm and density 10.5 g/cc is dropped in glycerine of…JEE Main 2023 (24 Jan, Shift 2)
Given below are two statements: One is labelled as Assertion A and the other is labelled…JEE Main 2022 (28 Jun, Shift 1)
The velocity of upper layer of water in a river is 36 kmh ⁻¹. Shearing stress between…JEE Main 2022 (25 Jun, Shift 1)
The terminal velocity of a copper ball of radius 5 mm falling through a tank of oil at…NEET 2022 (Phase 2)
The velocity of a small ball of mass 'm' and density d1, when dropped in a container…JEE Main 2022 (27 Jun, Shift 1)

Viscosity & Stokes' Law question from NEET 2023

More questions on Viscosity & Stokes' Law