Question

Ultrasonic waves have frequency

• A. below 20 Hz
• B. between 20 Hz and 20 kHz
• C. only above 20 kHz
• D. none

Answer 1

The correct option is C

only above 20 kHz

1. Ultrasonic wave is defined as “inaudible sound with high frequency for humans” the frequency of which generally exceeds 20 kHz.
2. These days, sound wave which is not intended to be heard is also called ultrasonic wave.

Hence, option C will be correct.