Frequency of ultrasonic preparation is:
Ultrasonic preparation: 

Consists of a peeso electric ceramic unit that generates ultrasonic waves which activate a magnetostrictive hand piece.
The hand piece produces movements of the shaft of the file between 0.001 to 0.004 inches in a frequency of 20,000 — 25,000 / sec.
NaOCI is used as irrigant solution.
Increased thermal and mechanical ability of the irrigating solution removes debris and tissue effectively and removal of smear layer is also efficient.
20,000 - 25000 cycles/ sec
5000 - 15000 cycles/ sec
30000 - 40000 cycles/ sec
1500 - 6500 cycles/ sec