Differentiate between ultrasonic and infrasonic sounds. What are the important uses of ultrasounds?

The difference between ultrasonic and infrasonic sounds:

Ultrasonic sound	Infrasonic sounds
1. Sounds of frequencies higher than $20KHz$.	1. Sounds of frequencies below than $20Hz$.
2. We can not hear these sounds	2. We can not hear these sounds
3. Bats produce this type of sound.	3. Vibrations of the pendulum.

The uses of ultrasound

1. It is used to detect flaws in any metal object.
2. It is used for ultrasonography.
3. It is used for ultrasonic cleaning.
4. Ultrasonic waves are used in medical imaging.