Question

What is the level of mercury at normal atmospheric pressure?
(a) 64 cm
(b) 70 cm
(c) 76 cm
(d) 80 cm

Answer 1

Hint: We will always measure atmospheric pressure in terms of Hg. Here, the symbol Hg represents mercury. Mercury has been included for measuring the value of atmospheric pressure at sea level because of the fact that mercury is present in the atmosphere.

Complete step by step answer:
Atmospheric pressure: We will define the atmospheric pressure which is present in the atmosphere. This pressure is generally created by the materials like mercury present in the atmosphere. This actually creates the pressure due to its weight. Atmospheric pressure is always measured by the use of a barometer and the value is calculated as the amount of force in a small unit of area. This helps us know the height of mercury which balances the atmosphere. There are several units which define atmospheric pressure and we can name them as millimeters of mercury or we can also use inches of mercury. The standard atmospheric pressure at the sea-level is 29.92 inches which after gets converted into centimeters gives us the value as 76 cm.
As there are mercury particles present in the air, they will have the same weight which will result in creating pressure and since these particles will exert gravitational forces due to which they create pressure at the level of the atmosphere above us all.

So, the correct answer is “Option C”.

Note: By the following points we will be able to get to know about the information of it through many sources of news for example television, internet and newspapers. The 76 cm of Hg is the value of the average atmospheric pressure at the sea-level. To get this value the scientists have taken many values under observation for finding this average value. One value was recorded in which the scientists got the highest measure of the atmospheric sea level and this value was 32.03 Hg.