Question

What are ultrasonics? Can you hear the ultrasonic sound?

Answer 1

The term "ultrasonic" applied to sound refers to anything above the frequencies of audible sound, and nominally includes anything over 20,000 Hz. Frequencies used for medical diagnostic ultrasound scans extend to 10 MHz and beyond.

No, we cannot hear ultrasonic sounds because it beyond our audible range. Animals like bats and dogs can hear them.