In Rutherford's alpha-particle scattering experiment, only a few...

In Rutherford's alpha-particle scattering experiment, the rebounding of alpha particles (scattering angle $\approx 180^{\circ}$) occurs when they undergo a head-on collision with the gold nucleus.

A head-on collision corresponds to an impact parameter close to zero. Since the size of the gold nucleus ($\approx 10^{-15}$ m) is extremely small compared to the size of the gold atom ($\approx 10^{-10}$ m), the effective target area is very small. Consequently, the probability of an alpha particle having a minimum impact parameter is very low.

Thus, only a few alpha particles undergo head-on collisions and rebound back. This makes statements A, C, and E correct.

Statement B is incorrect because the charge of an alpha particle is $+2e$ while the charge of a gold nucleus is $+79e$.

Statement D is incorrect because the alpha particles emitted from the radioactive source have nearly the same kinetic energy.

Answer: A, C, E Only