The Compton Effect and Scattering | Physics for EmSAT Achieve PDF Download

Introduction

• In physics, scattering refers to the alteration of a particle's motion direction due to a collision with another particle. The concept of collision, as defined in physics, encompasses interactions between particles that repel each other, even without direct physical contact. Subatomic particle experiments demonstrate that the repulsive electric force between particles adheres to Coulomb's law, which states that the force varies inversely with the square of the distance between the particles. In other words, if the distance is halved, the force quadruples. Experimental observations, depicted in the figure, reveal that the trajectory of the scattered particle, regardless of the deflection angle, takes the shape of a hyperbola. Additionally, as the incident particle is directed closer to the scattering center, the deflection angle increases.
• One notable instance of utilizing scattering in atomic exploration involved physicist Ernest Rutherford. Rutherford directed a stream of alpha particles, emitted by a radioactive substance and possessing sufficient energy to penetrate atoms, through a thin gold foil. Although most of the alpha particles passed through the foil unaffected, some were deflected in a manner indicating the presence of a Coulomb force. Since alpha particles bear a positive charge while the electrons within the atom carry a negative charge, it was inferred that a large positive charge existed within the atom, giving rise to the Coulomb force responsible for interacting with the alpha particles. This discovery led to the identification of the atomic nucleus.