Question

Most commonly known barometric fluid is

• A. Mercury
• B. Liquid oxygen
• C. Nitrogen
• D. Ammonia

Answer 1

The correct option is A Mercury

The first reason to use mercury is its high density. The atmospheric pressure measured by mercury barometer is the pressure equal to that at the bottom of the mercury column given by $h\rho g$.

Due to high value of $\rho$ the same pressure can be measured for smaller value of $h$.

Also the vapor pressure of mercury is negligible, due to which the barometric height is not affected.