For communication, elephants can make noises as loud as 103 decibels, but they often use low-frequency sound waves below 20 Hz, some of which travel through the ground. These low-frequency sounds are called:

What is the minimum distance a person must stand at from a reflecting surface to hear a distinct echo (assuming speed of sound in air is approximately 344 m/s)?

Sound in the human audible frequency range is commonly referred to as:

Assertion (A): Sound produced from a larger tabla is louder than sound produced from a smaller tabla when struck with equal force. Reason 1 (R1): Loudness increases with an increase in the surface area of the vibrating body. Reason 2 (R2): A larger tabla produces sound of a higher pitch.