A barometer correctly reads the atmospheric pressure as 76cm of mercury. Water droplets are slowly introduced into the barometer tube by a dropper. The height of the mercury column first decreases and then become constant. If the saturation vapour pressure at the atmospheric temperature is 0.80cm of mercury, find the height if the mercury column when it reaches its minimum value.

Explanation

To solve the problem, we will analyze the situation step by step.

### Step-by-Step Solution:

1. **Understand the Initial Conditions:**
The barometer reads an atmospheric pressure of 76 cm of mercury. This means that the pressure exerted by the atmosphere is equivalent to a column of mercury that is 76 cm high.

2. **Introduce Water Droplets:**
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