What does the double slit experiment demonstrate?

The double slit experiment is a fundamental experiment in physics that demonstrates the wave-particle duality of light and matter. When light (or particles like electrons) passes through two closely spaced slits, they produce an interference pattern on a screen behind the slits, which is characteristic of wave behavior. This pattern indicates that light behaves like a wave, as waves diffract and interfere with each other.

However, when the experiment is conducted with individual photons or electrons sent one at a time, each particle seems to also exhibit particle-like behavior, suggesting that they are localized entities. Yet, over time, even individual particles contribute to the same interference pattern, reinforcing the idea that they exhibit both wave-like and particle-like properties. This duality is a cornerstone of quantum mechanics and highlights how entities at the quantum level do not fit neatly into classical categories of behavior.

The other options misrepresent the findings of the experiment. The assertion that light only behaves as a wave or a particle overlooks the comprehensive evidence supporting the dual nature of light and matter. The notion that interference is not observable in light contradicts the core result of the experiment, which is precisely the observation of interference patterns. Thus, the correct answer acknowledges both the wave-like and particle-like behaviors demonstrated in this