In an experiment to verify Stokes law|VISCOSITY|JEEMAIN2020

JEE-MAIN 2020

05-09-2020 S2

Question

In an experiment to verify Stokes law, a small spherical ball of radius $r$ and density $\rho$ falls under gravity through a distance $h$ in air before entering a tank of water. If the terminal velocity of the ball inside water is same as its velocity just before entering the water surface, then the value of $h$ is proportional to (ignore viscosity of air)

Select the correct option:

$r^4$

$r^3$

$r^2$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution

$\begin{aligned} & \mathrm{V}_{\mathrm{T}} \propto \mathrm{r}^2 \\ & \sqrt{2 \mathrm{gh}} \propto \mathrm{r}^2 \\ & \Rightarrow \mathrm{~h} \propto \mathrm{r}^4\end{aligned}$

Question Tags

JEE Main

Physics

Easy

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