Eight small drops of mercury each of radius '$$r$$', coalesce to form a large single drop. The ratio of total surface energy before and after the change is

A spherical metal ball of radius '$$r$$' falls through viscous liquid with velocity '$$\mathrm{V}$$'. Another metal ball of same material but of radius $$\left(\frac{r}{3}\right)$$ falls through same liquid, then its terminal velocity will be

Select the WRONG statement from the following. In a streamline flow

Consider a soap film on a rectangular frame of wire of area $$3 \times 3 \mathrm{~cm}^2$$. If the area of the soap film is increased to $$5 \times 5 \mathrm{~cm}^2$$, the work done in the process will be (surface tension of soap solution is $$\left.2.5 \times 10^{-2} \mathrm{~N} / \mathrm{m}\right)$$