Question

A spherical soap bubble of radius $1cm$ is formed inside another of radius $3cm$. The radius of single soap bubble which maintains the same pressure differences as inside the smaller and outside the larger soap bubble is ________ $cm$.

• A. $1$
• B. $0.75$
• C. $0.5$
• D. $0.25$

Answer 1

The correct option is B $0.75$

As we all know, the pressure inside the soap bubble is= 2T/R

therefore, 2T/r +2T/r' = 2T/R

1/r+1/r'=1R

1/1+1/3=1/R

1/R=4/3

R=3/4 cm