Question

How much is the atmospheric pressure at sea level under NTP conditions?

Answer 1

1. The vertical height of the mercury column from the surface of the mercury in the trough is a measure of atmospheric pressure
2. At sea level, the level of mercury in the tube is $76cm$above the level of mercury in the trough.
3. Thus, the pressure equivalent to $76cm(or760mm)$ a high column of mercury is called one atmospheric pressure, i.e.,
4. 1 atmospheric pressure = $760mm$ of mercury column = $76cm$ of mercury column
5. The height of the mercury column in a glass tube does not depend upon its shape, size, and tilt.

Hence, the atmospheric pressure at sea level under NTP conditions is $760mm$