Question

To save money on buying mercury you build a BAROMETER using water as the fluid inside the column. Approximately, how tall is your barometer? (HINTS r(mercury) =1.36 x 10^4 kg/m^3 and r(water) = 1.00 x 10^3 kg/m^3).

Answer 1

To solve this problem we need to use the concepts related to fluid density. Since we need to know a height point of two different liquids, their pressures must be equal, so

$P_1 = P_2$

$\rho_1 gh_1 = \rho_2gh_2$

Where,

$\rho =$Density

g = Gravitational acceleration

h = Height

Our values are given as,

$\rho_1 = 1.36*10^4kg/m^3$

$\rho_2 = 1*10^3kg/m^3$

$h = 76.02cm \rightarrow$ Standard mercury pressure at 1atm, the barometer height is 760.2mm.

Replacing we have,

$1.36*10^4 *76.02= 10^3*h_2$

$h_2 = 1033.87cm$

Therefore the tall of the barometer would be 1033.87 (Inconvenient compared with the Mercury Barometer)