If a number of little droplets of water, each of radius `r`, coalesce to form a single drop of radius `R`, show that the rise in temperature will be given by `(3T)/J(1/r-1/R)` where `T` is the surface tension of water and `J` is the mechanical equivalent of heat.

Explanation

To solve the problem, we need to derive the rise in temperature when several small droplets of water coalesce into a larger droplet. We will follow these steps:

### Step 1: Volume Conservation
Let \( n \) be the number of small droplets, each with radius \( r \). The volume of one small droplet is given by:

\[ V_{\text{small}} = \frac{4}{3} \pi r^3 \]
...