The 10% of total volume of the barometer liquid (mercury) contains impurities having an average density `5 g cm^(-3)`. When this faulty barometer is used to measure the atmospheric pressure it reads 80 cm of the liquid column. Determine the correct atmospheric pressure.

Explanation

Volume of impurity= 0.1 V
Volume of `H_("mercury")` =0.9v
Density of the liquid in barometer = `("total mass")/("total volume")`
i.e `d_1=(d_Hg) xx 0.9V + d_("mercury" )/V`
Now the pressure recorded by a standard barometer
`p_1=h_(hg) d_y`
Presure recorded by faulty barometer
`p_2=h_2xxdlxxg`
Equate (1) and (2) and determine value at `h_(Hg)`
75 cm