Question: Two soap bubbles of radii r<sub>1</sub> and r<sub>2</sub> equal to 4cm and 5cm are touching each oth...

Question

Two soap bubbles of radii r₁ and r₂ equal to 4cm and 5cm are touching each other over a common surface $S_{1}S_{2}$ (shown in figure). Its radius will be

Answer 1

Solution

Radius of curvature of common surface of double bubble $r = \frac{r_{2}r_{1}}{r_{2} - r_{1}} = \frac{5 \times 4}{5 - 4} = 20cm$