JEE Main 2022 · 30 Jun · Shift 1 · Physics Q35

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PhysicsSingle correct+4 / -1Question 35 of 90

An air bubble of negligible weight having radius r rises steadily through a solution of density $\sigma$ at speed $v$ . The coefficient of viscosity of the solution is given by :

\eta=\dfrac{4r\sigma g}{9v}

\eta=\dfrac{2r^2\sigma g}{9v}

\eta=\dfrac{2\pi r^2\sigma g}{9v}

\eta=\dfrac{2r^2\sigma g}{3\pi v}

Answer and worked solution

Official answer: B

Terminal motion. Buoyancy $\frac43\pi r^3\sigma g$ balances drag $6\pi\eta rv$ : $\eta=\dfrac{2r^2\sigma g}{9v}$ .

(B)

Topics:Viscosity and Stokes' law Buoyancy and Archimedes' principle

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JEE Main 2022 · 30 Jun · Shift 1, Physics question 35