A bubble having surface tension T and radius R is formed on a ring of radius b `(b lt gt R)` . Air is blown inside the tube held in front of the ring , with velocity `upsilon` as shown in fig. The air molecules collides perpendicularly with the wall of the bubble and stops. Calculate the radius R at which the bubble and stops. Calculate the radius R at which the bubble separates from the ring.

Answer

B, D

Explanation

KEY CONCEPT: When the force due to excess pressure in the bubble equals the force of air striking at the bubble, the bubble will detach from the ring.
`:. rhoAv^2=(4T)/(R)xxAimpliesR=(4T)/(rhov^2)`