At the suggestion of Earnest Rutherford, hans Geiger and ernest Marsden bombarded a thin gold foil by `alpha`-particles from a polonium source. It was expected that `alpha`-particles would go right through the foil with hardly any deflection. Although, most of the alpha particles indeed were not deviated by much, a few were scattered through veryi large angles. Some were even scattered in the backward direction. The nly way to explain the results, rutherford found, was to picture an atom as being compoed of a tiny nucleus in which its positive charge and nearly all its mass are concentrated. Scattering of `alpha`-particles is proportional to target thickness and is inversely proportional to the fourth power of `sin((theta)/(2))`, where,` theta` is scattering angle. Distance of closest approach may be calculated as:
`r_("min")=(Z_(1)Z_(2)e^(2))/(4piepsi_(0)K)`
where, K=kinetic energy of `alpha`-particles.
Q. Rutherford's `alpha`-particle scattering led to the conclusion that: