Elephants communicate with one another at a sound frequency of
A) 1.0 Hz
B) 15 Hz
C) 150 Hz
D) 0.1 Hz

Hint: Frequency is number of times an event occurs per unit time. It is measured in units of hertz (Hz) that is equal to occurrence of any repeating event in a second.

Complete Answer:
1) Ultrasonic waves are the acoustic waves which are high in frequency which humans can't hear, however, infrasonic waves are the sound waves which have lower frequency than what we humans can hear. Ultrasonic waves can be defined as “the inaudible sound with high frequency for humans” the frequency of these waves generally exceeds 20 kHz.

2) Infrasonics or vibrational or stress waves in elastic media, having a frequency below those of sound waves that can be detected i.e., below 20 hertz. The range of frequencies is those which complete one cycle in 100 seconds or longer.

- The elephants have the peculiar characteristic of communicating using a very low sound frequency which is actually inaudible to the humans.
- Sound with low-frequency travels farther and faster compared to high-frequency sound which provides a secure long-distance communication for elephants.

Hence, the correct answer is option (A) 1.0 Hz.

Note: A subsonic wave is a wave which travels slower than the speed of sound whereas a supersonic wave can travel faster than sound wave.