Acoustics — Science STD 10 — Question

(i) Audible waves : These are sound waves with a frequency ranging between 20 Hz and 20,000 Hz. These are generated by vibrating bodies such as vocal cords, stretched strings etc.

(ii) Infrasonic waves : These are sound waves with a frequency below 20 Hz that cannot be heard by the human ear. eg: waves produced during earth quake, ocean waves, sound produced by whales, etc.

(iii) Ultrasonic waves : These are sound waves with a frequency greater than 20 kHz, Human ear cannot detect these waves, but certain creatures like mosquito, dogs, bats, dolphins can detect these waves, eg: waves produced by bats.