A source of alpha particles bombards a target of gold. A small fraction of alpha particles return in a direction opposite to that of the ingoing source particles. Which of the following statements accurately describes the cause of this phenomenon?
A)There is electrostatic repulsion between the alpha particles meeting a gold nucleus head-on.
B)The alpha particles are randomly scattered, and some return in the opposite direction.
C)The alpha particles feel the combined electrostatic forces of several gold nuclei acting in the opposite direction.
D)This never happens because the gold atoms are electrically neutral.

Question

Quizplus · Accepted Answer

The phenomenon described is due to the electrostatic repulsion between the positively charged alpha particles and the positively charged gold nuclei when they meet head-on. This is a classic demonstration of Rutherford's gold foil experiment, which helped establish the nuclear model of the atom.

A Source of Alpha Particles Bombards a Target of Gold