NDA2011General AbilityGeneral ScienceActual
Ultrasonic waves are those sound waves having frequency
Options
- Abetween 20 hertz and 1000 hertz
- Bbetween 1000 hertz and 20000 hertz
- Cmore than 20 kilohertz
- Dless than 20 hertz
Correct answer
C. more than 20 kilohertz
Step-by-step solution
The correct answer is option C