# What pressure to take in surface tension question?

Pressure inside a water droplet is $0.32 N/cm^2$ if surface tension of liquid is $0.095 N/m$. We have to find the radius of the bubble

since it's a water droplet the formula used is $$P_i-P_o=\frac{2T}{R}$$ The $P_i$ is internal pressure wehreas $P_0$ is external pressure so the $P_0$ should be taken in consideration but the solution of the question directly puts $0.32$ in place of pressure difference. where I am doing wrong in the question.

• How does 0.32 N/cm2 compare to atmospheric pressure? – Jeffrey J Weimer Sep 17 '18 at 12:55
• @JeffreyJWeimer sorry - you and me both mate! – Solar Mike Sep 17 '18 at 12:56
• @Wasabi answer is already in the question, OP just needed a pointer not a 5 page essay. – Solar Mike Sep 17 '18 at 14:45