question_answer

A soap bubble of radius R is surrounded by another soap bubble of radius 2R, as shown. Take surface tension\[=S\]. Then the pressure inside the smaller soap bubble, in excess of the atmospheric pressure, will be    

A) 4S/R

B) 3S/R               

C) 6S/R

D) None of these   

Correct Answer: C

Solution :

[c] \[{{P}_{1}}-{{P}_{0}}=\frac{4S}{2R}\,\,\]   ?..(i) \[{{P}_{2}}-{{P}_{1}}=\frac{4S}{R}\]        ?..(ii) Add (i) and (ii), \[{{P}_{2}}-{{P}_{0}}=\frac{6S}{R}\]