Two soap bubbles of equal radii (R=8cm) are stuck together with an intermediate film separating them. Surface tension of solution forming bubbles is 7x10^-3 Newton/meter.What will be distance between the centres of soap bubbles.(in cm)

Question

Two soap bubbles of equal radii (R=8cm) are stuck together with an intermediate  film separating them. Surface tension of solution forming bubbles is 7x10^-3 Newton/meter.What will be distance between the centres of soap bubbles.(in cm)

anonymous · Answer

should we find the thickness of the film separating? or is it negligible?

anonymous · Answer

no,this question has to be done probably using excess pressure and surface tension stuff..

anonymous · Answer

ok how about this when we say that the soap bubbles stick together without any movement,there is equal excess pressure extered by each of them on the surface of the film each being  equal to 4sigma/r
or else if the pressure at one was was highere than other, the bubble would burst asF=pressure*area both bubbles having same area (4pi*r^2)

are u interested in finding the small amount by which the bubbles expand due to excess pressure?