When two soap bubbles of radii r_1 and r_2 (r_2 lt r_1) adjoin, the radius of curvature of the common surface is

When two soap bubbles of radii r_1 and r_2 (r_2 lt r_1) adjoin, the ra

1.	When two soap bubbles of radii r_1 and r_2 (r_2 lt r_1) adjoin, the radius of curvature of the common surface is
Answer» `r_2-r_1` `r_2+r_1` `((r_2-r_1))/(r_1r_2)` `(r_1r_2)/(r_2-r_1)` Solution :If the ATMOSPHERIC pressure is `p_0` , then in case of the first bubble, `p_1-p_0=(4T)/(r_1) [ T=` surface TENSION of soap solution] In case of the second bubble, `p_2-p_0=(4T)/(r_2)` `therefore p_1-p_2=4T(1/r_1-1/r_2)` Again, if the radius of curvature of the COMMON surface is r, then , `p_1-p_2=(4T)/(r )` `therefore (4T)/(r )= 4T(1/r_1-1/r_2) or, 1/r=(r_2-r_1)/(r_1r_2) or, r=(r_1r_2)/(r_2-r_1)`