A soap bubble in air (two surfaces) has surface tension `0.03 Nm^(-1)`. Find the excess pressure inside a bubble of diameter 30 mm.

Options

A. 2 Pa
B. 4 Pa
C. 16 Pa
D. 8 Pa

Answer

D

Explanation

Excess pressure is given by , `p = (4S)/(r)`
Given, `S = 0.03 Nm^(-1)`
`r = (d)/(2) = (30)/(2) mm = (30)/(2) xx 10^(-3) m`
`rArr p = (4 xx 0.03)/(15 xx 10^(-3)) = 8 Pa`