Question

Ultrasound has frequency of vibration ___.

• A. between 20 and 20,000 Hz
• B. below 20 Hz
• C. above 20,000 Hz
• D. between 500 and 10,000 Hz

Answer 1

The correct option is C above 20,000 Hz

Ultrasound refers to sound with a frequency above 20,000 Hz. It is inaudible to human ears as the audible range of frequencies for humans is $20Hz$ to $20,000Hz$.