Some tropical gyrinid beetles (whirligig beetles) are colored byoptical interference that is due to scales whose alignment forms adiffraction grating (which uses scattered instead of transmitted light). If the incident light is perpendicular on the grating, the angle between the first-order maxima (on opposite sides of the zeroth-order maximum) is about 22°. What is the grating spacing of the beetle? Use 520 nm as the wavelength of light.