Question

An air bubble of radius $0.1\, cm$ is in a liquid having surface tension $0.06\, N/m$ and density $10^3\, kg/m^3$. The pressure inside the bubble is 1100 $Nm^{-2}$ greater than the atmospheric pressure. At what depth is the bubble below the surface of the liquid ? $(g = 9.8 \,ms^{-2})$

• A. 0.1 m
• B. 0.15 m
• C. 0.20 m
• D. 0.25 m

Answer 1

Answer: (A)

0.1 m

Answer 2

$h\,dg + \frac{LT}{r} = 1100$
$h \times 10^{3} \times 4.8 = 1100 - \frac{2\times 0.06}{0.1\times 10^{-2}}$
$= 980$
$h = \frac{980}{9.8\times 10^{3}} = 0.1\,m$