1000 drops of a liquid each of diameter 4 mm coalesce to form a single large drop. If surface tension of liquid is 35 `"dyn "cm^(-1)`, calculate the energy evolved by the system in the process.

Explanation

To solve the problem of calculating the energy evolved when 1000 drops of a liquid each with a diameter of 4 mm coalesce into a single large drop, we can follow these steps:

### Step 1: Calculate the radius of a small drop
The diameter of each small drop is given as 4 mm. Therefore, the radius \( r \) of each drop is:
\[ r = \frac{\text{diameter}}{2} = \frac{4 \text{ mm}}{2} = 2 \text{ mm} = 0.2 \text{ cm} \]

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