What is the smallest sound duration that the human can hear? In other words, what is the lower duration limit for a sound to be translated into electrical signals by the ear?

Suppose the human ear can discern or distinguish between 18 kHz and 20 kHz sounds, this would mean that, if a single wave could  be processed at 20 KHz, the sound duration would be 1 / (20KHz) = 0.00005 second, which would be next to incredible (and probably impossible).

I am particularly interested in the lower duration limit as depending on frequency.

I am expecting something like this (I am not sure)

     Freq   Duration needed to be aware of the sound
     20KHz  0.05S (50 mS)
     10KHz  0.04S (40 mS)
      5KHz  0.03S (30 mS)
    2.5KHZ  0.02S (20 mS)