If light wavelength is less than object diameter, light bounces off object {scattering, light}|. If light wavelength is more than object diameter, light goes around object.
example
Sky is blue, because blue light has small enough wavelength to scatter from air molecules, but other colors have longer wavelengths. Air molecules are large enough to block blue and some green light from Sun, but longer wavelengths go around air molecules. Scattered blue light goes all over sky to make it blue instead of clear. Sun is red at horizon, because light goes through more atmosphere to eye, and air scatters blue, green, and yellow light.
X-rays can have elastic scattering {Compton scattering} from stationary electrons in light elements. Scattered-radiation frequency decreases with increasing angle, so high frequencies are at narrow angles.
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Date Modified: 2022.0225