Question

Several spherical drops of a liquid of radius coalesce to form a single drop to radius $R$. If the surface tension and $V$ is volume and $r$ consideration, then the release of energy is :

• A. $3VT(\frac{1}{r}+\frac{1}{R})$
• B. $3VT(\frac{1}{r}-\frac{1}{R})$
• C. $VT(\frac{1}{r}-\frac{1}{R})$
• D. $VT(\frac{1}{r^2}+\frac{1}{R^2})$

Answer 1

The correct option is B $3VT(\frac{1}{r}-\frac{1}{R})$

Energy released

$=4\pi T{R}^3(\frac{1}{r}-\frac{1}{R})=3\left(\frac{4}{3}\pi R^3\right)T(\frac{1}{r}-\frac{1}{R})$

$=3VT(\frac{1}{r}-\frac{1}{R})$