The correct answer is: low-energy alpha particles passing through a field of low mass-number particles.
Explanation:
-
Alpha Particles: Alpha particles are positively charged and relatively heavy (made of 2 protons and 2 neutrons).
-
Deflection: The deflection of charged particles like alpha particles in a field is influenced by the mass and charge of the particles they interact with.
-
Energy of Alpha Particles: Low-energy alpha particles are less resistant to deflection because they have less momentum. Therefore, a lower initial kinetic energy results in a greater influence from an electromagnetic field.
-
Mass Number of Perturbing Particles: When alpha particles pass through particles with a low mass number, the interactions can result in greater deflections, as the lighter particles can change the direction of the alpha particles more readily compared to heavier particles. A high mass-number particle would be more massive and the effect of deflection might be minimized due to the greater inertia of the heavier target particles.
Overall, low-energy alpha particles encountering low mass-number particles will result in a greater deflection due to the combination of their lower momentum (making them more susceptible to changes in direction) and more effective interactions with the lighter particles.