Physics for IGCSE & O level - Waves And Sounds (Section 2 - No. 18)
What does the term 'ultrasound' refer to in terms of frequency?
Frequencies below 20 Hz
Frequencies between 20 Hz and 20 kHz
Frequencies above 20 kHz
Frequencies equal to 20 kHz
توضیح
The term ultrasound refers to frequencies above 20 kHz.