What Frequency is Needed for Ultrasonic Cleaning of 3.0 x 10^-2 cm Particles?

[VTC-nerds]

Homework Statement

Particles approximately 3.0 x 10^-2 cm in diameter are to be scrubbed loose from machine parts in an aqueous ultrasonic cleaning bath. Above what frequency should the bath be operated to produce wavelengths of this size and smaller?

Homework Equations

Fn = nv/(2L)
v= SQRT(F/Mew)
Mew=m/L
L=(n/2)Lambada
f=v/(lambada)

The Attempt at a Solution

So far I cannot come up with a beginning place on this one... I am thinking about using f=v/(lambada) but how would i come up with the velocity (v) without mew or F?

 

[learningphysics]

I think you just need to use: frequency = (speed of light)/wavelength

Use wavelength = 3.0*10^-2cm = 3.0*10^-4m

 

[mgb_phys]

It's an ultrasound cleaner so it's not the speed of light - it would be the speed of sound in the liquid.
You could just quote the frequency in terms of sound speed if you don't have a value.

 

[learningphysics]

It's an ultrasound cleaner so it's not the speed of light - it would be the speed of sound in the liquid.
You could just quote the frequency in terms of sound speed if you don't have a value.

Oops. Sorry about that.