Why does a column of mercury in a tube that is inverted in a dish of mercury have a height of about 760 at sea level?

The height of the Mercury column in an inverted tube at sea level is approximately 760 mm due to atmospheric pressure. At sea level, the average atmospheric pressure is about 101,325 pascals, which supports the weight of the mercury column. The density of mercury and the gravitational force together create a balance, allowing the column to reach this height. If the atmospheric pressure changes, the height of the mercury column will also change accordingly.