JEE MAIN - Physics (2024 - 30th January Evening Shift - No. 21)

A big drop is formed by coalescing 1000 small identical drops of water. If $$E_1$$ be the total surface energy of 1000 small drops of water and $$E_2$$ be the surface energy of single big drop of water, then $$E_1: E_2$$ is $$x: 1$$ where $$x=$$ ________.
Answer
10

Explanation

$$\begin{aligned} & \rho\left({ }_3^4 \pi r^3\right) 1000={ }_3^4 \pi R^3 \rho \\ & R=10 r \\ & E_1=1000 \times 4 \pi r^2 \times S \\ & E_2=4 \pi(10 r)^2 S \\ & \frac{E_1}{E_2}=\frac{10}{1}, x=10 \end{aligned}$$

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