The excess pressure inside a soap bubble of radius 6mm is balanced by 2mm column of all of density 800 `kgm^(-3)`. Find the surface tension of soap solution.

Options

A. `3.92 Nm^(-1)`
B. `0.0392 Nm^(-1)`
C. `0.392 Nm^(-1)`
D. `0.00392 Nm^(-1)`

Answer

B

Explanation

The excess pressure of soap bubble
`p=(4T)/(R) or hpg=(4T)/(R) (therefore hpg)`
`therefore T=(Rhpg)/(4)=(1xx10^(-2)xx2xx10^(-3)xx0.8xx9.8)/(4)`
`=0.0392 "Nm"^(-1)`