Question

Height of a mercury column is given as 76 cm of Hg in a barometer. Find the height of the column of a liquid of density 1.2 g/cc would be neccessary to balance atmospheric pressure
Given: Density of mercury = 13600 kg/$m^3$

• A. 546.8 cm
• B. 742.6 cm
• C. 432.5 cm
• D. 861.3 cm

Answer 1

The correct option is D 861.3 cm

Let the height of the mercury column be h cm.
Pressure corresponding to 76 cm height of mercury column = $\rho \times g\times h$ = $13.6\times g\times 76cm$
Pressure corresponding to height h = $1.2\times g\times hcm$
Equating them we get,
$13.6\times g\times 76cm$ = $1.2\times g\times hcm$
h = 861.3 cm