The interference pattern observed when electrons pass through a slit is a manifestation of wave-particle duality, a fundamental concept in quantum mechanics. Both electrons and light can exhibit wave-like properties under certain conditions.
In the case of light passing through two slits, the interference pattern occurs because light behaves as a wave and exhibits wave interference. When the light waves from the two slits overlap on a screen, they can either interfere constructively (peaks aligning with peaks) or destructively (peaks aligning with troughs), leading to bright and dark fringes, respectively.
Similarly, electrons, despite being particles, can also exhibit wave-like behavior. This phenomenon is described by the de Broglie wavelength, which associates a wavelength with particles. When electrons pass through a slit, their wave-like nature causes them to diffract and interfere with themselves, resulting in an interference pattern on a screen placed behind the slit.
The key difference lies in the mass and charge of electrons compared to photons (particles of light). Electrons are much more massive than photons, and they carry an electric charge. This difference in mass and charge affects the details of the interference pattern observed. However, the underlying principle of wave-particle duality remains the same for both electrons and light.
It is important to note that the behavior of particles at the quantum level is inherently probabilistic, and the interference pattern observed is the result of the statistical distribution of many individual electron or photon interactions.