Which postulate of Rutherford's theory is not derived from the results of `alpha`-ray scattering experiment ?
On what basis Rutherford's could assume that ?

Explanation

The postulate that the electrons revolve round the nucleus is not derived from the results of `alpha`-ray scattering experiment. The results of `alpha`-ray scattering gave the idea that entire positive charge is concentrated in a small part which is known as nucleus.
In order to counter balance the nuclear forces of attraction, the electrons revolve round the nucleus at very high speeds.