The smallest sound wave that can be detected by the human ear depends on various factors, including the individual's hearing sensitivity and the conditions in which the sound is present. In general, the human ear has a frequency range of approximately 20 Hz to 20,000 Hz, with the maximum sensitivity occurring around 1,000 to 4,000 Hz.
The threshold of hearing is defined as the minimum sound pressure level that can be detected by the average human ear under ideal conditions. This threshold varies with frequency, and typically the most sensitive range is between 2,000 Hz and 4,000 Hz.
At this range, the average threshold of hearing is approximately 0 decibels sound pressure level (dB SPL), which corresponds to the faintest sound that a young, healthy individual with normal hearing can detect. As the frequency deviates from this range, the threshold of hearing increases.
It's worth noting that individual variations in hearing acuity exist, and some people may have better or poorer hearing sensitivity compared to the average. Furthermore, factors like background noise, age, and hearing impairments can affect the ability to detect lower intensity sounds.
In summary, the smallest sound wave that can be detected by the human ear typically lies around the threshold of hearing, which is generally between 2,000 Hz and 4,000 Hz and has an intensity of approximately 0 dB SPL.