Given, diameter of air bubble, d=1mm =1×10−3m Viscosity, η=0.85N−s∕m2 Density, ρ=900kg∕m3 Air density, σ=1.293kg∕m3 Let terminal velocity be vT. ∵vT=
2
9
rg(
ρ−σ
η
) where, r is radius of bubble, ρ is density of bubble and σ is density of air. ∴vT=