Question

A bird produces an ultrasonic wave of wavelength 3.41 mm. Find its frequency if the velocity of the sound in air is 341 m/s.

Answer 1

given  wavelength = 3.41 mm = 0.00341 meters.

  frequency = velocity / wavelength = 341 m/sec / 0.00341 m
                  = 10^5 Hertz = 100 kHz

   It is ultra sonic, as it is more than 20 kHz. Humans cannot hear.  Perhaps it is a "bat" bird, that is producing this ultrasonic frequency.