¿Frequency of ultrasounds to obtain oil drops in water?

jonjacson

1. The problem statement, all variables and given/known data

To obtain microemulsions of oil into water ultrasounds are used. ¿What is the frequency to obtain oil drops of 1 microgram wich density is 0.995 g/cm3? (It does not need to be exact, with only the order of magnitude is sufficient).



2. Relevant equations

Well, I don't know if it is a diffraction problem, or If I should use resonance , or stationary waves.

I am lost at this point, I don't know wich physical principles rely behind this process of creating microemulsions.



3. The attempt at a solution

I am very sorry, but I don't understand the process.

Any idea to solve this will be well received.

I know that in physicsforums you should put the equations in the point 2, but I don't know what is the exact process.

Thanks in advance.

jonjacson

I have had an idea, I now what is the mass of the drops of oil, and the density so:

Volum=density/mass

I suppose that the drops are spherical, so they have a volum of 4/3*pi*r^3.

Finally I use:

V=[tex]\lambda[/tex] / [tex]T[/tex]

Where V is the speed of sound under water.

[tex]\lambda[/tex] Is the wavelenght of the wave.

[tex]T[/tex] is the period, or the inverse of the frequency.

So, using V=1500 m/s and a size of 0.013 meters I obtain:

Frequency [tex]\approx[/tex] 115384.6 Herzs


So I suppose that the interference pattern of the emitted wave will create oil drops of the size of the wavelenght, logically it is an approximation, I only need to know the order of magnitude of the frequency.

¿Do you think that this is correct?.

jonjacson

I should give this to my teacher on wednesday, soy please ¿do you have any idea about this?.