i'm a little confused... is rutherford's analysis actually valid, or is it partly valid?
It's partly valid in that it assumes the nucleus is a pointlike object. If the incoming alphas have enough energy, they can get close enough to the nucleus that the finite size of the nucleus and the structure of the nucleus have an effect on the scattering. And with enough energy, you can get a nuclear reaction instead of simple elastic scattering!
But Rutherford's original experiment used low-enough energy alphas that considerations like this didn't come into play, so his analysis was valid in that sense. Most analyses of physics experiments are like this, by the way.
yes... i was wondering if rutherford's analysis could be valid in all occasions, because he used classical physics... if classical physics fails to provide a meaningful analysis of atomic structure, then quantum mechanics should be used, right?