Question

What should be the pressure inside a small air bubble of 0.1mm radius situated just below the water surface? Surface tension of water = 7.2 × 10^-2 N/m and atmospheric pressure = 1.013 × 10⁵ N/m²? 

Answer 1

Radius of air bubble ; R = 0.1mm 

= 0.1 × 10^-3 m (1 mm=10^-3m)

Surface tension of water, T = 7.2 × 10^-2 N|m.

 The excess pressure inside an air bubble is given by :→

P₂ - P₁ = 2T/R

P₂ = Pressure inside air bubble

 P₁ = Atmospheric pressure