One of the fundamental experiments that demonstrated the wave nature of light and its relationship to wavelength and frequency is the double-slit experiment. This experiment provides evidence for the wave-particle duality of light.
The double-slit experiment involves shining a beam of light through two closely spaced slits onto a screen, creating an interference pattern. If light behaved solely as particles, one would expect to observe two separate bands of light corresponding to the two slits. However, what actually occurs is an interference pattern of alternating bright and dark bands, similar to what one would expect from the interference of waves.
This interference pattern arises due to the superposition of light waves from the two slits. When the peaks of two waves coincide, constructive interference occurs, resulting in a bright band. Conversely, when a peak and a trough coincide, destructive interference takes place, resulting in a dark band.
The key observation from this experiment is that the interference pattern remains intact even when individual photons (particles of light) are sent through the apparatus one at a time. Over time, as more and more photons pass through the slits, the interference pattern gradually emerges. This suggests that each photon behaves like a wave, interfering with itself and exhibiting wave-like properties.
The interference pattern can be explained by considering the wavelength and frequency of light. The distance between adjacent bright or dark bands in the pattern corresponds to the wavelength of the light. The frequency of the light determines how quickly the waves oscillate, and it is related to the energy of each photon.
By observing the double-slit interference pattern, scientists were able to conclude that light exhibits both wave and particle properties. This experiment played a crucial role in the development of quantum mechanics, which describes the behavior of particles on a microscopic scale, including photons.