(a) Calculate the height of a water column which will exert on it’s base the same pressure as the 70 cm column of mercury. Density of mercury is 13.6 g cm-3. (b) Will the height of the water column in part (a) change if the cross section of the water column is made wider ?

(a) Given,

h_m = 70 cm

ρ_m = 13.6 g cm^-3

ρ_w = 1 g cm^-3

Now, Pressure due to water column = Pressure due to mercury column

Hence,

h_w ρ_w g = h_m ρ_m g

⇒ h_w = h_m ρ_m/ρ_w

⇒ h_w = 13.6 × 70 / 1 = 952 cm = 9.52 m

Hence, the height of a water column = 9.52 m

(b) No, if the cross section of the water column is made wider, the height of the water column will be unaffected.