1. What is the sound of a tiger?
2. Which bird twitters?
3. What is necessary for sound to be produced?
4. What is the number of oscillations that an object per second called?
5. What is a sound of frequency less than 20 Hz called?
6. What is a sound of frequency higher than 20,000 Hz called?
7. Which mammal produces ultrasonic sounds while flying?
8. What is the ultrasound scanning of foetus inside the womb called?
9. What is measured by ultrasonic sounds?
Originally posted 2015-12-24 18:21:18.