A steel coin of thickness '$$\mathrm{d}$$' and density '$$\rho$$' is floating on water of surface tension '$$T$$'. The radius of the coin $$(R)$$ is [$$\mathrm{g}=$$ acceleration due to gravity]

The excess pressure inside a soap bubble of radius $$2 \mathrm{~cm}$$ is 50 dyne/cm$$^2$$. The surface tension is

'n' small drops of same size fall through air with constant velocity $$5 \mathrm{~cm} / \mathrm{s}$$. They coalesce to form a big drop. The terminal velocity of the big drop is

Pressure inside two soap bubbles are 1.01 atm and 1.03 atm. The ratio between their volumes is (Pressure outside the soap bubble is 1 atmosphere)