The height of the mercury column in a barometer at a place is 75 cm. If a liquid of unknown density is used the height of the liquid column is 150 cm, find its density.

Explanation

Since the atmospheric pressure is the same in both the cases,
`h_1d_1` = `h_2d_2`
The height of liquid column is double the height of the mercury column.
`therefore` its density should be half the density of mercury.
`therefore dl=(13.6)/2=6.8cm^(-3)`