Question

At sea level, atmospheric pressure is:
a) 76 cm of Hg column
b) 760 cm of Hg column
c) 0.76 cm of Hg column
d) 76 cm of water column

Answer 1

Hint: In order to answer this question, remember what is the definition of atmospheric pressure. Atmospheric pressure is defined as the pressure exerted by the atmosphere of the earth at the sea level under standard conditions.

Complete step by step answer:
As we know that:
Pressure at sea level is equal to 760 mm of Hg column.
Since 1 cm = 10 mm
So, 760 mm = 76 cm
Therefore, we can say that; at standard sea-level conditions, the atmospheric pressure is equal to 76 cm of Hg column.

So, the correct answer is “Option A”.

Additional Information:
Atmospheric pressure is expressed in several different systems of units: millimetres (or inches) of mercury, pounds per square inch (psi), dynes per square centimetre, millibars (mb), standard atmospheres, or kilopascals.

Note:
Atmospheric pressure is equal to force per unit area exerted by an atmospheric column, i.e. $P=\dfrac{F}{A}$. It is also known as barometric pressure because it can be measured by Barometer.
Barometer is an apparatus to measure the atmospheric pressure, which has mercury as a medium. The pressure difference across the tube causes the mercury to rise on one end and fall on the other. The difference of height of mercury in both the columns is used to find the atmospheric pressure.