An ice cube of edge $1 \mathrm{~cm}$ melts in a gravity free container. The approximate surface area of…

An ice cube of edge $1 \mathrm{~cm}$ melts in a gravity free container. The approximate surface area of water formed is (water is in the form of spherical drop)
  1. $(36 \pi)^{1 / 3} \mathrm{~cm}^2$
  2. $(24 \pi)^{1 / 3} \mathrm{~cm}^2$
  3. $(28 \pi)^{1 / 3} \mathrm{~cm}^2$
  4. $(12 \pi)^{1 / 3} \mathrm{~cm}^2$

Solution

$\mathrm{x}=1 \mathrm{~cm}$ $\therefore$ Volume of the cube $\mathrm{v}=\mathrm{x}^3=1 \mathrm{~cm}^3$, volume of drop $=$ volume of cube. $\begin{aligned} & \frac{4}{3} \pi r^3=x^3=1 \mathrm{~cm}^3 \\ & \therefore r^3=\frac{3}{4 \pi} \text { or } r=\left(\frac{3}{4 \pi}\right)^{\frac{1}{3}} \\ & \therefore r^2=\left(\frac{9}{16 \pi^2}\right)^{\frac{1}{3}} \end{aligned}$ Surface area of drop $=4 \pi r^2=4 \pi\left(\frac{9}{16 \pi^2}\right)^{\frac{1}{3}}$ $=\left(64 \pi^3 \times \frac{9}{16 \pi^2}\right)^{\frac{1}{3}}=(36 \pi)^{\frac{1}{3}}$

Asked in: MHT CET 2021 (24 Sep Shift 1)

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