Calculating Pressure Inside a Water Mist Droplet

[Derek1997]

Homework Statement

What's the gauge pressure inside a droplet of water mist of diameter 0.1 mm (radius 0.05 mm), assuming that the droplet is spherical? Use a water-air surface tension of 0.07 Jm\(^{-2}\) and specify your answer in bar /atmospheres (where 1 atmosphere pressure is \(1 \times 10^5\) Pa.

Homework Equations

delta P= 2*0.07/r (in meters)

The Attempt at a Solution

I subed the value inside the equation and i got 3000pa.. which is 3atm? am i right?

 

[gneill]

Homework Statement

What's the gauge pressure inside a droplet of water mist of diameter 0.1 mm (radius 0.05 mm), assuming that the droplet is spherical? Use a water-air surface tension of 0.07 Jm\(^{-2}\) and specify your answer in bar /atmospheres (where 1 atmosphere pressure is \(1 \times 10^5\) Pa.

Homework Equations

delta P= 2*0.07/r (in meters)

The Attempt at a Solution

I subed the value inside the equation and i got 3000pa.. which is 3atm? am i right?

It looks like you've chosen the correct formula to use, and your result in Pascals looks good to me for one significant figure of accuracy. Note however that an atm is not 1000 Pa; One atm is to be taken as 10⁵ or 100,000 Pa according to the definition you're given in the problem statement.

 

[Derek1997]

so 0.03?

 

[gneill]

so 0.03?

Yes, that looks like a good value. Be sure to always specify units on any values that you present!