Answer to Question #120698 in Electricity and Magnetism for Gift

Question

A bat can detect small objects, such as an insect, whose size is approximately equal to one wavelength Of sound the bat makes, if bat's emit a chirp at a frequency of 6.00 × 10⁴ Hz, and if the speed of sound in air is 343m/s, what is the smallest insect a bat can detect?

Answer 1

If the frequency is $f$ and the speed of sound is $v$ , then the wavelength can be calculated as (see https://en.wikipedia.org/wiki/Wavelength)

$\lambda = \dfrac{v}{f} = \dfrac{343\,\mathrm{m/s}}{6.00\times10^4\,\mathrm{Hz}} = 5.7\cdot10^{-3}\,\mathrm{m} = 5.7\,\mathrm{mm}.$