Radius of a capillary is $2\times {10}^{-3} \mathrm{m}$. A liquid of weight $6.28\times {10}^{-4} \mathrm{N}$ may remain in the tube if surface tension of the liquid will be:

The excess of pressure in a soap bubble of radius r is proportional to

An oil drop falls through the air with a terminal velocity of $5 \times {10}^{–4} \mathrm{m} {\mathrm{s}}^{-1}$. The radius of the drop will be: $\eta =3.6\times {10}^{-5 }\mathrm{N} \mathrm{s} {\mathrm{m}}^{-2}, {\mathrm{\rho }}_{\mathrm{oil}}=900 \mathrm{kg} {\mathrm{m}}^{-3}$.,$g=10 \mathrm{m} {\mathrm{s}}^{-2}$

Neglect the density of air as compared to oil.