Hi! In a book, there is stated that the least detectable object by a bat is when the object is λ/2 of the sound wavelength emitted by the bat. I know there is resolution criteria for light microscopes too, which concerns the wavelength of the light. My question is: Are these criteria about the phenomena of interference of waves or something else? Or maybe it is possible to detect the objects smaller than this size, but we can not get any information about size or form from them if the wavelength is too long?