Two soap bubbles of radii r1 and r2 equal to 4 cm and 5 cm are touching each other over a common surface S1 and S2 shown in figure. Its radius will be :

Question

Two soap bubbles of radii r1 and r2 equal to 4 cm and 5 cm are touching each other over a common surface S1 and S2 shown in figure. Its radius will be : (A) 4.5 cm (B) 25 cm (C) 20 cm (D) 40 cm

Tardigrade Admin · Accepted Answer

Radius of curvature of common surface of double bubble r=(r2 r1/r2-r1)=(5 × 4/5-4)=20 cm

Q. Two soap bubbles of radii $r_{1}$ and $r_{2}$ equal to $4 c m$ and $5 c m$ are touching each other over a common surface $S_{1}$ and $S_{2}$ shown in figure. Its radius will be :

4.5 cm

25 cm

20 cm

40 cm

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

Q. Two soap bubbles of radii r1​ and r2​ equal to 4cm and 5cm are touching each other over a common surface S1​ and S2​ shown in figure. Its radius will be :