Q.

The excess pressure inside a soap bubble is thrice the excess pressure inside a second soap bubble. The ratio between the volume of the first and the second bubble is     [2024]

1 1 : 9  
2 1 : 3  
3 1 : 81  
4 1 : 27  

Ans.

(4)

Excess pressure in soap bubble =4SR

Given P1=3P2    P1=4SR1 and P2=4SR2

3P2=4SR1;  R1=4S3P2;  R2=4SP2

R1R2=4S3P2×P24S=13

Ratio between the volumes V1V2=43πR1343πR23=127