A glass tube having 2 mm bore is dipped vertically into a vessel containing mercury such that its lower end is 8 cm below the mercury surface. Determine the gauge pressure of air in the tube to blow a hemispherical bubble at its lower end. Take, density of mercury =13.6 "g/cm"^(3) Surface tension of mercury = 36 dyne/cm

A glass tube having 2 mm bore is dipped vertically into a vessel conta

1.	A glass tube having 2 mm bore is dipped vertically into a vessel containing mercury such that its lower end is 8 cm below the mercury surface. Determine the gauge pressure of air in the tube to blow a hemispherical bubble at its lower end. Take, density of mercury =13.6 "g/cm"^(3) Surface tension of mercury = 36 dyne/cm
Answer» Solution :GIVEN, `r=(2mm)/(2)=1 MM =0.1cm` `sigma ="35 dyne/cm"` `rho=13.6 "g/cm"^(3)` h=3cm Pressure of air = Excess pressure inside air bubble + Pressure exerted by mercury column `=(2 sigma)/(r)+HPG` `=(2 xx 35)/(0.1) +3 xx 13.6 xx 980` `=700+39984` `=40684" dyne/cm"^(2)`