a. what is the amplitude of the sound wave that represents hearing
Each Hz represents one wave cycle per second. If our ears are working perfectly, we can hear frequencies from about 20 Hz (for example, the largest organ pipe) to 20,000 Hz (for example, some dog whistles). As we move away from the source of a sound, the pressure drops approximately in proportion to the distance. As the distance from the sound source doubles in length, the sound pressure level is reduced by half. The height and depth of sound waves is referred to as amplitude or loudness. As the amplitude increases, the volume increases. Our ears can detect sound over a very wide range of amplitudes, which are often measured and described in terms of decibels (dB). The softest sound humans can hear is approximately 0 dB.