Prove that if two bubbles of radii `r_(1)` and `r_(2)(r_(1)ltr_(2))` come in contact with each other then the radius of curvature of the common surface `r=(r_(1)r_(2))/(r_(2)-r_(1))`
A. `r = (r_(1)+r_(2))/(2)`
B. `r = (r_(1)r_(2))/(r_(1)-r_(2))`
C. `r = (r_(1)r_(2))/(r_(1)+r_(2))`
D. `r = sqrt(r_(1)r_(2))`
