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JEE MAIN 2023
11-4-2023
Question
Eight equal drops of water are falling through air with a steady speed of 10 cm/s. If the drops coalesce, the new velocity is:-
Select the correct option:
A
10 cm/s
B
40 cm/s
C
16 cm/s
D
5 cm/s
✓ Correct! Well done.
✗ Incorrect. Try again or view the solution.
Solution
$\begin{array}{ll}\text { Sol. } & v \propto r^2 \\ & \frac{v_1}{v_2}=\left(\frac{r}{R}\right)^2 \\ 8 \cdot \frac{4}{3} \pi \pi^3=\frac{4}{3} \pi R^3 \\ R=2 r \\ \frac{10}{v_2}=\left(\frac{1}{2}\right)^2 \\ v_2=40 \mathrm{~cm} / \mathrm{s}\end{array}$
Question Tags
JEE Main
Chemistry
Medium
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