Are EM waves scattered the most when the wavelength and the obstacle have a similar size?

I heard that when the wavelength and obstacle are similar in size, the scattering is the greatest. Is this true?

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What do you mean by "scattered most?" This seems to only have an obvious definition for billiard-ball type scattering. –  santa claus Mar 26 '13 at 0:37
Do you mean only elastic scattering? Do you include inelastic scattering? –  Ben Crowell Mar 26 '13 at 5:12
Please define "the greatest".. –  user22772 Apr 4 '13 at 20:18
As a possible reformulation, allow me to suggest that you pick a generic but realistic scatterer. A spherical dielectric made of quartz, for example, in free space. Then calculate (or look up) the scattering amplitude as a function of the frequency of the incident field. You can do the whole problem analytically and you will get useful, generic insight. Your results should match ray theory at high frequency, Rayleigh scattering at low frequency with Mie in the middle. Hope that helps. PS, how you handle the small attenuation is nontrivial. –  user27777 Aug 17 '13 at 22:34